Talk:UniModal

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This article was nominated for deletion on 17 May 2006. The result of the discussion was no consensus.

Some of the content of this page has been archived at Talk:UniModal/archive. Most recent archive was moved there: 26 June 2006.

Contents 1 Current Status 2 My biggest gripe 3 Unverified or questionable information 4 Keep it real. 5 Virgin 6 Visually Impaired readers 7 "these pods exist" 7.1 Part deux 8 Rollback 9 "few moving parts" comment 10 Deleted line revisited 11 less is.. less? 12 Wow 13 Gross misunderstanding 14 A Series of Interesting Points

[edit] Current Status

Does anyone what the current status is of SkyTran? Are they planning to build a demonstration line anytime soon?

[edit] My biggest gripe

It's 2006 and we still don't have even a small demonstration system. I think it's a hoax. Think about it for a second. If SkyTran really did what Malewicki claimed it would, and at the price that he quotes ($1 million per mile to build, cost ten cents per mile to ride), every big city in the U.S. would have it by now.

Doug, either build the sucker, or go away. Please!

• Oh, if it were that simple. Cobble together $20M and start slapping together a few miles of guideways, some stations, a couple dozen cars, a maintenance facility, and get the show on the road. What different world this would be. --JJLatWiki 01:24, 8 September 2006 (UTC)
  • There's lots of sources for venture capital. $20 million should be relatively easy to raise, especially since this project has so much potential. Doug, get off your a$$ and do it!

Capital is the easy part -- trying to get over the political hump is by far the more difficult proposition. PRT is the worst kind of political baggage for a politician: risky, expensive, controversial, and long term (i.e.: won't be finished before the next election). Compounding the political problem is the rampant misinformation campaign being waged by people like you-know-who, making the bad political situation even worse.

That's why I think many have begun focusing on private applications and/or airports. Large airports are the best possibility for initial deployment, because they already have the land, they have a need for efficient transportation, they have the capital to spend, and (most importantly) they don't have anywhere near the political battle that a city installation has. It's no surprise, IMO, that ULTra has gotten further than anyone by partnering with an airport.

In Malewicki's case, my guess is he got frustrated with battling politicians and finally gave up on actively pursuing projects. He's an idea man, an inventor, and probably didn't have the patience (or desire) to continue fighting the political battle. But that's just my uninformed opinion. ATren (formerly A Transportation Enthusiast) 16:00, 8 September 2006 (UTC)

Basically he's an all talk and no action man. He doesn't even have a scale model of his SkyTran vehicle, let alone a small 100 yard demonstration system. (SkyWeb Express does)

[edit] Unverified or questionable information

Guideway

(industrial poles can be variably sized to accommodate a range of conditions)

One mile of guideway (both directions) has been reported to have a calculated capacity of 14'400 pods per hour.

Although the guideways have been reported to be about one million dollars per mile, more recent reports of about 2 million dollars per mile have been made. Currently, the company says they are claiming $10 million per mile, but say that the reason for this is to make their cost analysis seem more believable, and they hold that their actual estimates are still well below that amount.

Although, like most PRT, the inventor suggests a guideway grid, the UniModal design permits guideways to be used in any configuration - such as a linear route system (like most train routes).

Costs

Projected estimates:

• Installation cost: less than $10m per mile ^[1]
• Energy cost: Between $0.01 to $0.02 per pod-mile ^[2]
• Suggested end-user price: $0.10 to $0.20 per pod-mile (about the cost of gasoline for a car) ^[2]

Pods

Projected estimates:

• 10 feet long
• 200 pounds (passengerless)
• Cost: ~ $3000
• Payload weight capacity: 700 pounds

Pods would travel at up to 100 mph within cities. Trips between cities would reach 150 mph, increasing the estimated energy usage per mile by approximately 3 times (according to the drag equation).

The pods are designed to be pressure washed.

The designers argue that handles are not only inconvenient in the general case, but are a huge danger in emergencies especially (people might be tempted to open the doors to a 30 foot drop to the ground).

Pods would have a small battery, so that a pod could reach the next station and safely disembark its passenger even in complete system failure.

The doors of the pod would not have handles (inside or out), but would open automatically. However, a door release mechanism would be on the outside of the pod to allow rescuers to open the door.

Semantics

A Pod is the name of the vehicles in the UniModal system. The reasons for the name are psychological - people associate "cars" with traffic, insurance, crashes, and gas prices. The name pod is meant to reduce these connotations.

Portals are stair-structures where people get on an off pods. Since people associate the words "station" and "stop" with buses, trains, and long waits, the word portal is again used to avoid these connotations.

Guideways are the "tracks" that the pods travel on. This word is used in many PRT proposals, probably also for psychological reasons.

Many of these connections may be unconsciously thought of and for these reasons, new words have been created to describe a system in which these connections are not present.

Importance of weight and speed

The advantage of a small vehicle is that it weighs less, and therefore requires less support - allowing a smaller, less expensive guideway. Also, smaller cars are cheaper to build and have less aerodynamic drag. Making pods twice the size would most probably increase the cost of the system more than 2 or 3 fold. The system is designed to relieve commuter congestion - the main reason that the average car in the U.S. carries 1.16 people.

One advantage of Unimodal's high speeds is that trips would be faster. Another important reason to have higher speeds is that higher speeds increase capacity - a singly pod could be used more times in, say, an hour. This is a factor in saving money because the only other ways to increase capacity are to build more guideways, or more vehicles.

Ideal Guideway Grid

Ideally, Skytran/UniModal would be built in a grid configuration, where parallel guideways would be built one mile apart and portals would be build every mile along each guideway. This configuration would require a maximum 1/2 mile distance to the nearest portal, and an average distance of 800 feet (about a 3 minute walk at 3 mph walking speed).

Although a guideway grid would be most convenient for users, and most efficient for the system, the UniModal design permits guideways to be used in any configuration - such as a linear route system (like most train routes).

Deceleration - tracks, and brakes

The design proposes that vehicles slow down to 20 mph on the deceleration guideway before actually making any turn. Regenerative braking would be supplemented by an emergency brake with a maximum deceleration of 6 G. The pods would have seatbelts resembling race car seatbelts - with a wider belt and an X shaped harness - to lessen the pressure in an emergency stop.

This deceleration rate was chosen in order to enable vehicles at 1-second headways to comply with rail safety standards requiring that a public transportation vehicle must be such a distance behind the vehicle in front of it to make a complete stop in that distance. Note that rail safety standards do not yet apply to PRT systems, and that this braking rate is considered unsafe for the general population by most authorities.

For each 90 degree turn onto a guideway perpendicular to the current guideway, there will be a deceleration track, turn track, and an acceleration guideway. Vehicles would exit the main guideway, then decelerate to 20 mph during the turn, and then accelerate back up to 100 mph to enter the main guideway again.

The emergency brake would be a pad that presses against the inside of the steel rail, permitting fast emergency deceleration. The designers cite that a six G (about 59 m / s²) deceleration would be safe in the short period of time (about 3/4 of a second). The deceleration rate allows a vehicle traveling at 100 mph to stop in less than 17 meters (56 feet).

Pods would travel 72 feet (or about 1/2 second) from each other. Since guideway supports are spaced 36 feet apart, only one pod can be between support posts at a time - meaning supports need only be able to support the weight of one pod.

Like all PRT systems, before vehicles stop, they would exit the main guideway, then slow and then stop on a deceleration guideway. This is analogous to the way cars exit a freeway, rather than remaining on the road. This allows the main guideway to maintain a constant speed.

Envisaged trip

A person would approach an entrance portal, walk up the stairs, and get in the ready pod. One would tell (verbally) the pod where to go, and the pod door would close automatically. The pod would then accelerate forward and up along the acceleration guideway, and would then merge with the main guideway at 100 mph. The pod would travel toward the destination portal and would exit on the decelerate track, slow down, and presently stop at an exit portal. The door would automatically open, and the person would get out and walk down the stairs. The pod would then close its door, and edge forward to wait in a line with other pods, all waiting for people to use the pod in front at the entrance portal.

Pods would travel at up to 100 mph within cities. Trips between cities would reach 150 mph, increasing the estimated energy usage per mile by approximately 3 times (according to the drag equation).

The SkyTran designers suggest that providing a door-to-door taxi service would be the most economical way to provide for the disabled, thus indirectly satisfying any relevant laws or regulations.

Magnetic levitation

Inductrack permits low magnetic drag. At 100 mph, a 700 pound UniModal vehicle requires 408 watts (0.547 horsepower) to overcome this magnetic drag. By constrast, a 700 pound car-like vehicle traveling at 100 mph would use about 4 times this much. For comparison, conventional cars (varying between 2200 and 3500 pounds with coefficients of rolling friction of between 0.011 and 0.03) traveling at 65 mph consume between 3000 and 13,500 watts in order to overcome the tire resistance (not counting air resistance).^[3]

Tire resistance is significant at low speeds (say around 10 mph where a car might require around 7000 W to overcome air drag), but at higher speeds air drag becomes much more significant (say at 100 mph, a car might require around 60,000 W to overcome air drag).

Sources

• globalideasbank.org
• www.swedetrack.com - mentions "People Pod" a former name for UniModal.
• [1] - mentions skytran has interest in building at Santa Cruz.
• www.transpowerusa.com

[edit] Keep it real.

UniMOdal has been compared in the past to freedom ship. Actually Personal rapid transit is analogous to the freeodm ship article, but that's by the by. This article needs to remain as a small and verifiable treatment of a concept which has no real existence. No prototype + no patent = no article, usually; in this case you are absolutely determined ot have an article, so that article needs to restirct itself to facts. Which does not mean a salesman's view of the facts. Just zis Guy you know? 23:20, 9 June 2006 (UTC)

This page says theres multiple patents. I disagree with your comparison of freedom ship to Personal rapid transit, as freedom ship is one company, and PRT is a design concept used by many companies over a period of about 50 years. I disagree with your edits, and I suppose I will re-add the things you deleted with explanation on this page. We worked very hard to verify everything in the article JzG. Fresheneesz 01:15, 10 June 2006 (UTC)

Your continued comparison of PRT to Freedom Ship is baffling to me. Does Freedom Ship have 30 years of research behind it? Are there entire volumes written about the theory of Freedom Ship? Did the US government sponsor extensive research into Freedom Ship in the 1970s? Did the Japanese government develop and test a Freedom Ship? Does the German government have a fully designed, tested, and approved Freedom Ship waiting for deployment? Does Heathrow Airport plan to install a Freedom Ship in the next year? Are test Freedom Ships being built in Sweden? Is there an open contract for construction of a Freedom Ship in Dubai? Are there half a dozen companies actively working on Freedom Ship implementations on three continents? Let's get real here: comparing PRT to Freedom Ship is absurd.

Skytran and Freedom Ship are actually very similar. Freedom Ship is a concept proposed by a single individual, which is an extension to existing technology (very large cruise ships). There is little more than a plan, and skeptics believe it's impractical to build. How is this different than SkyTran?

Freedom Ship has a small article, and SkyTran deserves one too. I agree the old one was a bit too long and needed to be shortened, but your continued insistence that Freedom Ship is analogous to PRT (as opposed to SkyTran) is indefensible. A Transportation Enthusiast 18:27, 10 June 2006 (UTC)

I wasn't the one who started with the freedom ship analogy. As far as I'm concerned this is probably more like an article on a concept car by a designer who has not as yet had a car produced. If the article gets no bigger than it is, continues to make it plain that this is a fantasy and not a reality, and does not begin to repeat the highly speculative claims as to costs etc., then I am happy enough. I remain unconvinced that any large scale PRT project will be built; I am doubly unconvinced that it will be this one, lacking as it does any track record (pun intended). Just zis Guy you know? 19:11, 10 June 2006 (UTC)

I just want to remind you that it doesn't matter if you are convinced that it will be large-scale. We're not trying to predict the future here. If SkyTran NEVER got developed, I still think it would be a very interesting and informative article to have 100 years from now. You don't think so? Fresheneesz 20:09, 10 June 2006 (UTC)

Regarding PRT (not SkyTran): as an analogy, what about Blu-Ray? It's just emerging in the digital video marketplace (it's been delayed), and although the technical issues are largely resolved, there are big questions as to whether it will succeed commercially given its competition with HD-DVD. Let's say I am convinced that Blu-Ray will not succeed; does that give me the right to "balance" the Blu-Ray article by truncating it in size and adding unanswered criticism everywhere? Can I add a section claiming that Blu-Ray will never be able to compete cost-wise with HD-DVD, with links to HD-DVD advocacy pages as part of my argument? Can I accuse Blu-Ray proponents of deliberately attempting to kill digital video by fractioning the market? Can I quote Hitachi criticisms of Blu-Ray without quoting the Sony response? Can I fill the entire Blu-Ray article with "theoretically" and "could be" and "Blu-Ray proponents claim" even for topics that are unquestionably true, just because we don't want to give the impression that Blu-Ray is available yet? Can I justify all this solely by calling myself a "Blu-Ray skeptic"? A Transportation Enthusiast 22:07, 10 June 2006 (UTC)

Blu-Ray is like PRT: an unproven technology. This is like one company's implementation of BluRay - and the company actually has no products currently on the market. PRT is an interesting, if unproven conept; UniModal is one man's fantasy of what PRT might look like. Treated on that basis, it is fine (except for the small problem that Malewicki does not appear to be a mainstream figure in transportation; if this was Ford's blue sky concept it would be a much more compelling keep). The major problem in respect of UniModal is that it is a political concept and is pushed by politicians. It is hard to separate the project from their agenda. A reader who sees an article describing a cheap and credible means of transportation will have been duped: what they should see is an article describing one man's concept for a system which is unproven on anything like the scale envisioned. Wikipedia is not Myspace. Just zis Guy you know? 13:18, 11 June 2006 (UTC)

Yes, I know, I was comparing Blu-Ray to PRT. Perhaps I should have asked this question on the PRT page, because I'm not talking about Unimodal but rather PRT in general.

The question I have is, if I am a Blu-Ray skeptic, does that give me the right to arbitrarily shorten the Blu-Ray page, add unanswered criticism from HD-DVD proponents, and sprinkle "could theoretically" and "proponents claim" everywhere in the Blu-Ray article, even for uncontested facts? That's what you've insisted be done for PRT, the transit equivalent of Blu-Ray. My question is, why shouldn't the Blu-Ray (and, for that matter, HD-DVD) be presented the exact same way as PRT is now, i.e. littered with skepticism and disclaimers? A Transportation Enthusiast 17:57, 11 June 2006 (UTC)

If it asserts things which are speculative, then absolutely. That's the whole point of WP: NPOV absolutely requires that we show the balance of informed opinion, which means that the sceptical view must be given more prominence if it is the majority view (as it is, with PRT, for good reasons). Just zis Guy you know? 10:05, 12 June 2006 (UTC)

So you would support me if I went and overhauled Blu-Ray (and even HD-DVD) with "proponents claim" for all assertions about specifications and such, and change "is" to "could... if proponent claims are realized" everywhere? I would do this for every single claim that hasn't been validated commercially, i.e. basically everything about Blu-Ray. Because Blu-Ray does not exist. Would that be the correct approach? Should I start applying this to every single piece of technology ever created that has not yet succeeded in the commercial marketplace? A Transportation Enthusiast 10:44, 12 June 2006 (UTC)

JzG, how does WP reconcile "informed majority view"? And assuming said "IMV" leans against the opinion of the proponent, why does is translate into pruning of every "unverifiable" fact from the overall article and repeated reminders that "this is just a concept"? If "verifiable facts" were the minimum criteria for a lengthy entry in WP, Dictionary.com would have longer entries for "blackhole", "global warming", "Dvorak keyboard", and many others. Couldn't we, as interested contributors, or WP at large agree to some semi-generic phrase that covers everything, like, This article describes a pure design concept that uses different technologies that may themselves be purely or partially conceptual with no real-world installation or even prototype. As such, many of the conclusions are concept estimates and should not be accepted as undisputed facts. That being said, I would disagree that it's even possible for WP to reflect the "balance of informed opinion" or for WP to ascertain a majority view. I doubt anyone has data that indicates scepticism is the majority view of PRT, much less a more defined concept like UniModel. I've seen a handful of people editing the PRT article and read the PRT opinion web sites, so the "informed opinion" headcount appears to be no more than a couple dozen people. Hardly enough to pronounce a majority or balance.

I would agree to draconian edits to remove "wild-ass-guesses" and violations of physical laws, with the obvious exception of most contemporary quantum mechanics theories, anything acknowledged as supernatural, and works of fiction. If the UniModal concept asserted that passenger pods would travel at supersonic speeds and use less energy than a 40 watt lightbulb to transport 3 passengers 10 miles, then there is a clear call to raise the BS flag and demand some supporting documentation. But all the disputes I've read regarding PRT involve whether the computer models are accurate, whether certain headways are possible or within the comfort level of the average person, or whether the construction costs can be as low as the designers claim. In all these arguements, the counterpoint is either theoretical itself or simply an opposing opinion. Opposing opinion on PRT seems to result in a quick removal of the disputed claim and leaving little for people seeking information to research.--JJLatWiki 22:27, 12 June 2006 (UTC)

There is not even a test track. Most of what is written is necessarily speculative and WP:NOT a crystal ball. Just zis Guy you know? 22:52, 12 June 2006 (UTC)

The long-term effects of Global Warming are speculative, yet they're presented as evidential and inevitable outcomes in WP. Are these articles also earmarked for deletion or truncation: Mars Direct, Aurora Programme, Crew Exploration Vehicle, Stem cell treatments, Quantum computer, and many others? Most of those articles have simple statements that they are "proposals" or "theoretical" or, in the case of "stem cell treatments", "Medical researchers believe that stem cell treatments have the potential...". Just because some people speculate that PRT can't work, doesn't mean that PRT is deserving of less bits in cyberspace than LRT. All the information contributed on PRT and here for UniModal has been presented as theoretical and/or conceptual proposals somewhere either in printed publications or now on the web. Counter-opinion doesn't justify removal of whole articles or significant portions thereof. In fact, I think it's a disservice to WP researchers. I, for one, like to find conceptual proposals in WP based on the speculative integration of unproven theories like PRT and previously unrelated technologies. Even "proposals" for a new computer keyboard that uses OLED technology to change the key caps is interesting to find, even if it's speculative. I'm with you if someone says, "Hey I got an idea, what if we dangled a little Disney roller-coaster cab under a monorail and use maglev to push it around. I think I'll call it, 'i-Taxi'." or "Like your car...but faster." But PRT has been in development for decades around the world, and been in various prototype stages for years. UniModal is a particular design with a few years of development itself. That doesn't make WP a "crystal ball". A crystal ball is, "In the year 2012, 30% of the city of London will be serviced by UniModal PRT". Dismissing theories, concepts, and ideas because "there is not even a test track" is not helping researchers interested in the concept. Should all books be removed from the college library if they discuss concepts that aren't even in prototype development? I hope not.--JJLatWiki 00:28, 13 June 2006 (UTC)

Last time I looked at that article it was based on citations from multiple authors in multiple peer-reviewed journals and included discussion of the minority view that man-made global warming is not a fact. Are you going to keep choosing unrelated examples iuntil you find one that fits your preconceptions, or are you going to run with Virgin, HST and Freedom Ship, where the approach is entirely consistent? Just zis Guy you know? 07:09, 16 June 2006 (UTC)

"which means that the sceptical view must be given more prominence if it is the majority view (as it is, with PRT, for good reasons)" - JzG - Please prove this to me, where is this vast majority that has verifiable sources for sceptical views on PRT? Fresheneesz 22:24, 14 June 2006 (UTC)

Reversal of the burden of proof (and requiring proof of a negative). You prove that this is widely discussed in the mainstream of transportation debate and technical journals. I can't find any such evidence. I can find evidence that UniModal is a theoretical concept only, with no funding, no prototype, no orders and no obvious imminent prospect of any. This article is acceptably neutral, I'd like to see a really good reason why it should be changed. Just zis Guy you know? 10:35, 15 June 2006 (UTC)

JzG: he was asking about PRT, not UniModal.

Fresheneesz: JzG and I have already had a spirited debate on this very topic (the "majority view") on his talk page. It's still going on if you want to take a look. A Transportation Enthusiast 12:59, 15 June 2006 (UTC)

Update: JzG archived the entire discussion (which was still active) so if you want to see it look in the PRT archive on his talk page. A Transportation Enthusiast 16:40, 15 June 2006 (UTC)

How many places do you want to have the same discussion at once? Just zis Guy you know? 07:06, 16 June 2006 (UTC)

Three. :-) A Transportation Enthusiast 14:46, 16 June 2006 (UTC)

JzG, you're the one with the burden of proof here. You said, "the sceptical view must be given more prominence if it is the majority view (as it is, with PRT, for good reasons)." You assert that there is a majority view. You assert that there are good reasons to be sceptical. Furthermore, you are not simply doubting or questioning the claims, you assert that the claims of PRT proponents and the UniModal designer are not taking adequate factors into account. I will not argue that UniModal's estimate is accurate. I will argue that they made the claim and that the claim is a germane to the article. Your position and discussion suggests that any WP article you touch that includes a dollar estimate, that estimate has been scrutinized by you and you know that all pertinent factors have been adequately considered in the estimate, including metalurgy, government regulations, energy costs, local labor costs, rights of way, property values, etc., etc. It's a relief to know you're an expert in all those areas. --JJLatWiki 20:27, 15 June 2006 (UTC)

A common misconception among those pushing a particular point of view, that content must not be removed unless provably false; actually policy has it the other way round: it must not be included unless verifiably true. My position is that we don't include marketing information unless we can verify its neutrality - whicih in this case we can't. Just zis Guy you know? 07:06, 16 June 2006 (UTC)

Agreed. In which case, "the sceptical view must be given more prominence" is *not* what we want to do if "the sceptical view" is not verifiable. Fresheneesz 05:13, 18 June 2006 (UTC)

Neutrality of marketing information? That's almost an oxymoron. But I'm glad you put your engineering expertise to bear and verified that Virgin Galactic's $200K estimate is accurate. Now I am extremely confident that when the time comes, I absolutely can take out a 2nd on my house to take a ride. By the way, does this mean that you've verified UniModal's "100 mph" claim? The article doesn't say "high speed", so I assume you've verified they can actually go 100 mph.

Also, I wasn't talking about proving aspects of the article, only proving the factual assertions that you make, like, "majority view". You made a factual statement that has been called into question several times and you deflect the scepticism by claiming the other person is employing some logical fallacy.

And in case you're wondering, I can verify and would swear under oath that SkyTran estimated $1m/mile and that estimate did NOT include the cost of the vehicles themselves and was NOT based on the use of Inductrack technology. --JJLatWiki 20:24, 19 June 2006 (UTC)

I know for a fact SkyTran did not base its estimates of the guideway on vehicals in any way. They separate those costs, and estimated vehicals costing $3000 a peice. Fresheneesz 22:57, 19 June 2006 (UTC)

I actually recently saw a source that said vehicles are estimated at $4000 to $6000 each. Fresheneesz 06:46, 20 June 2006 (UTC)

All this reinforces the fact that we have no reliable cost data. How many pods? Who knows. Depends in large part on the eventual regulatory framework. Just zis Guy you know? 09:13, 21 June 2006 (UTC)

[edit] Virgin

"The Virgin boss has signed a £14m, 15-year licensing deal with Mojave Aerospace Ventures - the outfit financed by MS co-founder Paul Allen - to build five Rutan-designed vehicles. " [2]. This is not comparible with Unimodal, which we all agree is a nice design but is no where near this stage of realness. Stephen B Streater 20:39, 15 June 2006 (UTC)

That same group have probably not invested much into any form of urban transit. The government has a clear monoply on urban transit that has a ready supply of funding coerced from people who don't use it. Why would anyone with a couple hundred million dollars of disposable income drop it on a system that will benefit the lowest tax bracket dwellers more than any other group? Send one little pod into orbit with your name on the side and the world stops to watch it on TV and repeats the name, "Virgin". Send a couple hundred little pods around an urban center and see if CNN stops their regularly scheduled program to cover the action.  ;) --JJLatWiki 23:43, 15 June 2006 (UTC)

Railways in Britain were financed by private money. It's only since WW2 that they have been publicly owned. And they have huge subsidies because passengers wouldn't pay the true cost, and non-passengers benefit, and people have just got used to them. Stephen B Streater 06:21, 16 June 2006 (UTC)

Passenger rail was privately built and run in the U.S. also until the AmTrak government monoply was created. AmTrak, like all government run transit systems, could not exist without HEAVY government subsidy for the same reason: passengers would never be willing to pay the true cost of a government run transit system. --JJLatWiki 15:25, 16 June 2006 (UTC)

I was told as a student that the only passenger rail system which runs in profit without subsidy is the bullet train. But I wouldn't believe it without a decent source. Just zis Guy you know? 17:21, 16 June 2006 (UTC)

Interesting fact. Given the Japanese system of government, I imagine it would difficult quantify. But interesting none the less. --JJLatWiki 18:32, 16 June 2006 (UTC)

[edit] Visually Impaired readers

I have a family member who is visually impaired and I've worked with youngsters who are visually impaired and I have a problem with one of Stephen B Streater's changes that removed the design description of pods being suspended from the overhead track. The justification was that the image makes it clear and I presume that therefor the description is redundant. I disagree with the decision and the reasoning. Visually impaired readers may only hear the description or read it in braille. Furthermore, a picture could depict one form of a particular proposal. One might assume that UniModal's distinguishing features are maglev, voice recognition, and tandem seating, and the picture is just one design variation that happens to be suspended from an overhead track. That's not fair to all readers and more so for the visually impaired. --JJLatWiki 15:48, 16 June 2006 (UTC)

Good point. I think the information is verifiably part or the design, and I did not consider visually impaired readers when I made this change. I'll add in a phrase to cover this point. Stephen B Streater 16:25, 16 June 2006 (UTC)

[edit] "these pods exist"

JzG insists on this line: "For example, the New Haven Advocate states that "these pods exist" [3] despite the fact that no prototype has been built."

It is a clear misreading of the source, which implies that the idea exists - its a freaking metaphor. This is innaccurate and horribly unverified original research.

Am I the only person that has a problem with the fact that that line violates all three major official policies? Fresheneesz 06:51, 20 June 2006 (UTC)

It says "these pods exist". They don't. You say the idea exists. Not outside the mind of Douglas Malewicki, it doesn't. In fact, the whole tone of the piece is promotional and it avoids mentioning the awkward facts that (a) no prototype exists and (b) no city in the world has a comparable system - some sentences could actualky be construed as implying the opposite. So this is a cited example supporting the fact, which we stated without your disputing it, that much of the coverage is not neutral. Just zis Guy you know? 13:59, 20 June 2006 (UTC)

The first third of the article is a flash-forward of a hypothetical future. Maybe thats why you think they imply it already exists. Btw, I'm not saying that that article isn't biased - I am strictly arguing against the line you put in about "these pods exist" - which I have already argued against - and you have avoided ALL of my points. JzG, you're pushing clear POV. Fresheneesz 17:50, 20 June 2006 (UTC)

This may not be the only interpretation, but to me the flash forward ends with the multiple blank lines and the present restarts at "A scene from The Jetsons?". Stephen B Streater 19:05, 20 June 2006 (UTC)

To me it looks like the author is trying to give the impression that the pods exist in physical form. Is there any evidence that this is a metaphor? Stephen B Streater 08:01, 21 June 2006 (UTC)

I think this is if not the only then certainly a valid and likely interpretation of the article as written. It seems to me that the intent is perfectly plain: to portray this as an extant system. Just zis Guy you know? 08:39, 21 June 2006 (UTC)

Fine. Its just my interpretation. But yours is only your interpretation too. And its very fair to say that articles on UniModal are in most cases biased in favor of UniModal. However, please explain to me how your individual interpretations of the article isn't OR. Fresheneesz 08:00, 22 June 2006 (UTC)

The piece says what it says. My interpretation is literal, and shared as you see by Stephen. If you want us to read between the lines and interpret the piece as being allegorical, then that would be OR. Just zis Guy you know? 11:01, 22 June 2006 (UTC)

You can't take a metaphor and interpret it literally. Any interpretation, literal or not, is OR. Fresheneesz 20:44, 22 June 2006 (UTC)

Exactly right. So we take it at face value: it says these pods exist, but they don't. It's misleading. Just zis Guy you know? 20:46, 22 June 2006 (UTC)

You're misinterpretting what I said. Is that a straw man? I'm unclear as to what exactly that means.. Fresheneesz 21:35, 22 June 2006 (UTC)

Er, what? I thought I was agreeing with your statement that interpretation is OR; I therefore fall back on not interpreting it, but taking it at face value precisely as stated. If you want to know what a straw man is, you'll need an encyclopaedia... Just zis Guy you know? 21:49, 22 June 2006 (UTC)

Yea, I actually meant that "taking it at face value" is an interpretation - and a wrong one if the author meant it as a metaphor. Problem is that we don't know what the author meant, and as such have our own interpretations.

"you'll need an encyclopaedia" - crap, but I hate reading : ( Fresheneesz 22:51, 22 June 2006 (UTC)

[edit] Part deux

I finally read the New Haven "these pods exist" piece to see why this has raised so much ire. I think there's some grey area, but in my opinion, the statement, "These pods exist." was not meant as a metaphor. I also do not think this is a good example of "pro-PRT bias". I can imagine similar misrepresentations when the Concord was in the design stages. Maybe something like, "Imagine being able to take off from Paris just after breakfast and flying faster than the sun to arrive in New York City in time for breakfast the same day. Fantasy? Not anymore. This plane exists." While the pods don't physically exist, the reporter could be under the misguided impression that they do. Or the reporter could be leaving out the usual puff-piece rhetorical, "...at least in computer simulations." That doesn't imply bias though. Bias requires more intent.

Furthermore, this "controversy" is related more toward general PRT, than this particular flavor. In fact, now that I see "controversy" and this one single quote, I'm inclined to say that there is apparently NO controversy surrounding UniModal. For a controversy, there must be some dispute, which implies at least one opposing view. So maybe if we keep the "Controversy" header, it should simply say that UniModal suffers from the same controversies as the general PRT concept. As it is, it seems more like a dispute over grammar. --JJLatWiki 15:54, 19 July 2006 (UTC)

It's just an example of the way that this particular PRT proposal is puffed. Advertisement masquerading as editorial. Guy 15:42, 2 October 2006 (UTC)

And the source for this judgement is...? ATren 15:54, 2 October 2006 (UTC)

...unnecessary. It's an example. Guy 15:58, 2 October 2006 (UTC)

No, it's a statement which, when subjected to analysis (i.e. original research), may be construed to be evidence of a theory - that Unimodal is controversial - which is not documented elsewhere. You are not merely citing the quote, you are interpreting it and stating a conclusion that has not been documented in any reliable source. It is therefore original research and inappropriate. ATren 16:49, 2 October 2006 (UTC)

My point exactly. There seems to be no controversy of this quote whatsoever, WP talk aside. This isn't an example of controversy, indicative of any controversy, or biased. It's a typical puff piece that is common to just about every kind of technology with which the reporter is unfamiliar, and sensationalization is a better way to get the reporter's name in print or on the air. Beside the pages of WP and maybe of one rabid anti-PRT zealot, what I'm asking is, where is the evidence of the controversy over this statement or position? --JJLatWiki 21:57, 2 October 2006 (UTC)

[edit] Rollback

Fresheneesz, your last edit was quite unacceptable. Not only did it include significant editorialising, it was self-referential and included personal attacks. Do not do this again. Just zis Guy you know? 09:15, 21 June 2006 (UTC)

Sorry JzG. You could find those citations quite easily yourself. Why didn't you? And even now, you removed my numerous citations, but didn't remove "citation needed". What gives? I beg of you, can you please try not to annoy the shit out of me anymore? I promise to try harder back. That should be a policy WP:DATSooP - try and figure out what that stands for. Fresheneesz 08:03, 22 June 2006 (UTC)

See below: the problem was not as you represent it. Do remember that the burden of proof is with you when you insert a claim into the text. Also, the terminology "comparable applications" is IMO better than "applications comparable to transit". A speech recognition system in, for example, a catalogue showroom, woudl arguably be a reasonable pilot for this, being a system designed to regonise a wide range of voices and allow choices from a long list of options - that's an invented example, obviously, but you get the drift - it doesn't need to be transit to be comparable to the application of public / many users / many choices. Just zis Guy you know? 11:04, 22 June 2006 (UTC)

Alright, that makes sense. However, the "applications comparable to transit" refers to comparing to transit, not being transit applications. Its a small point, but I worry that "comparable applications" might make some readers wonder what applications we're talking about, and what we're comparing to specifically. Fresheneesz 20:42, 22 June 2006 (UTC)

I think you're over-analysing it. I reckon the average reader will have little trouble understanding the meaning without narrowing it. Just zis Guy you know? 20:45, 22 June 2006 (UTC)

[edit] "few moving parts" comment

I tagged the para "For economy and reliability, the system design has few moving parts" as requiring citation because of the following concerns:

• What qualifies as "few"? By comparison with what? By whose judgment, other than those trying to sell the system?
• How do we prove that this will result in improved economy? It may be cheaper to buy conventional alternatives which are not solid-state
• How do we verify that this will increase reliability? Custom solid-state components in first-generation applications may be unreliable

It looks likie a marketing claim. Just zis Guy you know? 10:05, 21 June 2006 (UTC)

Its widely recognized that moving parts cause problems. Things that don't move don't die as easily. First gen anything isn't going to be super spiffy, but solid state has more potential than non-solid state. Also, you can count the moving parts - do you want us to write that in? Theres the door, the actual pod, the wheels to support non-moving pods, potential AC units.. thats it. So yea, you can do the math - how many moving parts are in a train? 500.. thousand? Fresheneesz 08:10, 22 June 2006 (UTC)

It's also "widely recognised" that stock parts cause fewer problems than custom ones. Trains are built to modular designs so that any failed part is lifted out and replaced with an identical one, and mean times between failures can be very high indeed (as can service lives). But as usual you evaded the point: the claim weas marketing hype. The revised wording is better but still promotional in tone. Just zis Guy you know? 10:57, 22 June 2006 (UTC)

Ah, well yes, the wording was hypish, but I think the current wording is much less so. As for custom parts, I would think that skytran would use custom parts even if they decided to reject the maglev idea. Fresheneesz 20:39, 22 June 2006 (UTC)

I'm sure they would. The contrast with ULTra is striking: there, they have made a virtue of using stock parts. Just zis Guy you know? 20:44, 22 June 2006 (UTC)

And that was a very good plan for Ultra, but UniModal couldn't be the same thing if it used only stock parts - although it could use some. Fresheneesz 21:33, 22 June 2006 (UTC)

In other words, bleeding edge technology... Just zis Guy you know? 21:57, 22 June 2006 (UTC)

[edit] Deleted line revisited

"In the past, the company has estimated a possible $1 million per mile once in mass production."

Comments on how to add this information in, in a way everyone can be comfortable with? Fresheneesz 03:16, 25 June 2006 (UTC)

You will be unsurprised that since their last guesstimate got increased by a factor of ten, I think this has no place in the article. It's not just that there is nothing with whihc to compare it, we don't even know if the design would stand up to operational stresses. There are simply too many unknowns. Just zis Guy you know? 22:13, 27 June 2006 (UTC)

[edit] less is.. less?

" in comparable applications, such as speech recognition"

JzG thinks that this is better than "in applications comparable to transit, such as speech recognition". I think that one can easily miss-read the first sentence in this way "comparable applications such as speech recognition". Its an awkward way to write it and might force readers to re-read that sentence several times before getting it right. Fresheneesz 03:19, 25 June 2006 (UTC)

This wording is too restrictive though, as the speech recognition might become proven in a comparable environment which is not directly transit related. This would still indictate its viability in a transit setting. I suggest something like: The Unimodal system design includes a number of technologies which are either unproven or untried in comparable applications. Such technologies include speech recognition to interact with riders, and electric linear propulsion using a form of passive magnetic levitation called Inductrack. Stephen B Streater 08:48, 25 June 2006 (UTC)

That could work. One point tho: if the application is comparable to transit applications, then couldn't that application still not be transit related? For example, I would say that a speech-recognition vending machine would be comparable to transit applications. Fresheneesz 00:25, 26 June 2006 (UTC)

The way I was reading applications comparable to transit was that the application itself was comparable, not the speech recognition environment itself. Stephen B Streater 06:13, 26 June 2006 (UTC)

Ohh, not quite the way I was reading it. I was thinking more that the way the application was used (or whatever) was comparable. Maybe that part needs some completely different wording. Fresheneesz 18:18, 26 June 2006 (UTC)

How about: The Unimodal system design includes a number of technologies which are either unproven or untried in comparable situations. Such technologies include speech recognition to interact with riders, and electric linear propulsion using a form of passive magnetic levitation called Inductrack. Stephen B Streater 21:41, 26 June 2006 (UTC)

That sounds more clear. Fresheneesz 23:25, 26 June 2006 (UTC)

OK - Let's try it for a bit. Stephen B Streater 06:23, 27 June 2006 (UTC)

I think this last version is perfect. A Transportation Enthusiast 20:48, 27 June 2006 (UTC)

I always find a team effort with a good result most satisfying :-) Stephen B Streater 20:58, 27 June 2006 (UTC)

I too have no dispute with the new language. Sounds neutral and tells the complete story. I have 2 very minor points... first, a question. MS Word grammar checker always suggests changing "which" to "that", and so I've gotten used to using "that", partially to avoid MS Word nags. Second, I think electric linear propulsion is not as untried in transit as maglev and especially Inductrack. So, how do you feel about this: "The Unimodal system design includes a number of technologies that are either unproven or untried in comparable situations. Such technologies include speech recognition to interact with riders, and a passive form of magnetic levitation called Inductrack." --JJLatWiki 22:33, 27 June 2006 (UTC)

Perhaps "that" is an American thing. I wouldn't assume MS grammar checking is a reliable source ;-) (but it doesn't seem obviously wrong either). Normally I would go for more concise but am interested in evidence that electric linear propulsion has been proven. Last I heard, it didn't work very well for trains because of power requirements. That doesn't mean we should keep it, as the rest of the sentence contains all the information relevant to Unimodal. Stephen B Streater 06:37, 28 June 2006 (UTC)

Bombardier Advanced Rapid Transit systems use electric linear propulsion. A Transportation Enthusiast 14:53, 28 June 2006 (UTC)

The idea of "passive magnetic levitation" is a curious one; it's not passive as such, it's just that the coils are located on the vehicle not in the track. Passive track maglev would be better. Just zis Guy you know? 07:12, 28 June 2006 (UTC)

Personally I think "which" flows better, (and i'm american) but whatever. And passive maglev is purely passive. Inductrak uses passive soilenoids inside the track, and passive permenant magnets in the vehical. The only power needed to levetate the vehicle is the energy needed to accellerate the vehicle up to speed, and the energy needed to overcome whatever resitance to keep it at speed. Its not only the track that is passive. Fresheneesz 08:17, 28 June 2006 (UTC)

It's not passive, though, since it requires propulsive effort. That's confiusing. It suggests that an unpowered car will levitate. Just zis Guy you know? 08:43, 28 June 2006 (UTC)

I have a problem with Inductrack being characterized as "passive" also, but that's what it says in the Inductrack article. It seems truly passive maglev would use only permanent magnets in the track and the car, but I haven't read enough on it to contribute to Inductrack. --JJLatWiki 13:32, 28 June 2006 (UTC)

As I understand it, it is passive in the sense that there is no power required to levitate other than then that which is required for propulsion. In other words, if you had some external means of propulsion, the vehicle itself would levitate without power. Does this mean it's completely passive? No, because generally vehicles can't generally move without power. But, for example, I think if you had a train of linked vehicles, only the front car would need power, to propel the whole train, which would then levitate.

Of course, there is current flowing in an Inductrack coils, it's just induced current. Which leads me to a question: how much back force is introduced by the induction? Presumably, at higher speeds it's less than the frictional force of wheels, or there would be no point, right? (More thinking) It seems that the back force would be relatively constant wrt speed, since the weight of the vehicle doesn't change with higher speeds (ignoring relativistic effects :-)), so the higher the speed, the less of a factor the inductive back force is. A Transportation Enthusiast 15:11, 28 June 2006 (UTC)

I don't know if the utilization of the electrical energy created by the motion of the permanent magnets is completely passive or if it uses active switching. But, if the Inductrack article says "passive", then characterizing it here as passive seems safe.

It seems to me that the energy conservation law implies that the "back force" would be considerable and require significant energy to overcome. Probably not less than wheels, but I don't think reduced energy consumption by reducing wheel friction is the driving force (figuratively) behind maglev. The energy conservation law implies that the energy required to levitate a train is the same regardless of how the levitation is accomplished. It takes the same amount of electricity passing through the coils in the track to levitate a train whether the coils are powered by an external source or by induction from the train passing over them. So, if that's the case, the "power" in the Inductrack coils comes from the propulsion, which must therefore be considerably more powerful than the propulsion system in a split system (separate levitation and propulsion systems). Inductrack probably requires no MORE electricty than a split system, but because the propulsion system provides the power for levitation AND propulsion, the vehicle will still consume significant electricity that is substantially the same as a split system. --JJLatWiki 16:59, 28 June 2006 (UTC)

Linear induction motor have some history, even in transit. Maglev has almost exclusively experimental history, because most maglev techniques require significant energy to levitate. So I personally think it's safe to disassociate electric linear propulsion from maglev. --JJLatWiki 13:32, 28 June 2006 (UTC)

The levitation is passive. The car will levitate with NO ENERGY INPUT (provided that the car already be traveling above the speed neccessary for levitation). Because its passive, it uses up 0 energy when the vehical is not inputting energy into linear motion. Passive is a very useful qualifier, and the fact that it uses energy at all is like saying that the repulsion of two permenant magnets isn't passive either - because you have to push them together in the first place. <- not a good reason to call something active. Fresheneesz 19:33, 28 June 2006 (UTC)

From an individual component viewpoint, Inductrack can be considered passive, because it does not require a direct energy source. But it does consume energy -- it draws from the kinetic energy of linear motion, which must be supplied by something. So while the component itself might be considered passive, it still relies on some other mechanism to provide the kinetic energy it needs to operate.

In a sense, Inductrack seems to be just an elegant form of wireless energy transfer: some external energy source drives the linear motion, which in turn transfers electromagnetic energy to the track-based coils as the vehicle magnets pass over, which induces the repulsive magnetic force. It's interesting in that the transmitted energy is never converted back to electrical current but rather is consumed directly as magnetic energy. Very neat technology, even if not strictly "passive" from a whole system standpoint. A Transportation Enthusiast 20:13, 28 June 2006 (UTC)

"I don't think reduced energy consumption by reducing wheel friction is the driving force behind maglev"

I totally maybe sorta disagree. Of course there is hopfully reduced maintenance cost (because of less moving parts), but energy usage to overcome friction is a large issue. Car wheels use up lots of a cars energy input at lower speeds, and still a significant percentage at higher speeds. On the SkyTran website, it says that LLNL found that the coefficient of magnetic resistance is the equivalent of a .003 rolling coefficient - which is very much less than cars' usual .01 or .015. Fresheneesz 19:40, 28 June 2006 (UTC)

fewer moving parts don't always equate to reduced maintenance costs. In the case of maglev, I bet the cost of replacing broken or burnt out coils will be greater than the normal 3 rails of an electric train. But, the main advantages of maglev come at high speeds where the rolling wheels generate more heat, resulting in more wear and tear, and where ride comfort becomes more and more difficult to maintain. The cost of maintaining the rails for the Japanese Shinkansen and the French TGV is high because passengers complain about bumpy rides compared to the 30 mph jaunts on urban Light Rail. I assume you are refering to the tires of an automobile when you said "car wheels use up lots of energy". That's mostly true because the tires are soft rubber on a low pressure carcass, which isn't a fair comparison to any transit system except busses. I think .001 is about what the tires on a racing bike in velodrome measure, and about the same as a steel train wheel on a steel track. Inductrack seems to offer a more robust form of levitation with natural stability and less need for active failsafe mechanisms and so is probably a better fit for a passenger application. But do they actually claim to use less energy? And I guess it's "passive" in the same sense that some electronic components are described as "passive", like a capacitor or resistor. --JJLatWiki 23:37, 28 June 2006 (UTC)

You're right that fewer moving parts don't always mean less maintenance cost, but it does usally mean less maintenance - ie longer MTBF. I suppose I was pulling the "less energy use" thing out of my ass, because I was using cars as my sole example. I'm pretty sure they don't claim "less energy use", they do however claim their tested lift to drag ratio of 0.380081, which malawiki said was equivalent to the .003 crr. [4] So yea, i'll back down on my statement of "I totally disagree". I'll change that to "I maybe sorta disagree".

On thinking more about this, I think probably the main benefit of maglev over other levetation schemes (like wheels) is that it is (or has the potential to be) cheaper and generally more convenient at higher speeds. However I'll stand strong on the point you don't dispute about passive maglev : ) Fresheneesz 09:11, 29 June 2006 (UTC)

Yah, I think maglev really shines at high speed. But "high-speed" raises concern for an urban transit scenario. High-speed just isn't comfortable for short commute loops that will have to have numerous twists and turns. I understand that the Inductrack people claim levitation even at slow speeds, but it seems that the natural stability of Inductrack is greater at higher speeds, so for passenger comfort, you want to be moving at high speeds. If it's the case that the UniModal pods will levitate at 5 MPH but only become comfortably stable at 50 MPH, then intra-city loops will probably have to run on wheels and transition to Inductrack for longer inter-city legs. Either that or they'll have to add some active stabilization for low-speed operation. --JJLatWiki 15:06, 29 June 2006 (UTC)

This is a fair point, I'd say. Once again, there is no data on which to base a realistic view. But the passive debate has been interesting :-) Just zis Guy you know? 16:38, 29 June 2006 (UTC)

Then to add a little substance to the "passive" debate, I looked it up on Dictionary.com. According to the American Heritage Dictionary, "passive" in electronics means, "Exhibiting no gain or contributing no energy". It seems a little broad in scope, but do these short-circuited loops of wire qualify as "passive"? Is the levitation "passive" if magnets MUST be moving past the coils? This isn't the same as 2 magnets attracting or repelling each other because they are doing so whether or not they are moving. Inductrack requires motion first. A mechanical analogy might be a lever. Without energy applied to one end, the other end can do no work. But is a lever "passive"? --JJLatWiki 18:15, 29 June 2006 (UTC)

Well since neither inductrack nor a lever, nor capacitors or resistors, can exhibit gain, then I guess they qualify as passive. I guess the catch is that one will never truely obtain "gain" if you're looking at all inputs to a system. Part of the definition of passive vs active assumes that active elements have a power source that is part of the element (rather than an input to the element). I guess its pretty much an arbitrary classification - but a useful one in circuit theory. Fresheneesz 19:04, 29 June 2006 (UTC)

Here's the Scientific American article on Inductrack, linked from the Inductrack article. A lot of the questions raised here are answered there.

I do now see it as a passive system in the sense that there is no direct power input to the levitation system -- the capacitor/resistor analogy is illuminating. This IMO is a huge benefit for failsafe operation (someone above alluded to this). If a superconducting maglev loses power, the refrigeration units stop running, causing the magnets warm up and lose their magnetism, causing the train to de-levitate even if it is running at full speed. Therefore, such systems require complex designs to account for power failures. With Inductrack, the levitation power source is the very movement of the vehicle, so it is inherently failsafe.

Furthermore, as the article linked above points out, the levitation is very stable by virtue of the magnetic field effects dropping off exponentially (or is it geometrically?) as the gap distance increases. So there's a nice stable equlibrium at the exact gap distance where the magnetic force just balances the opposing gravitational force: too close and the magnetic repulsion dominates; too far and the magnetic force quickly drops below the gravitational pull. It's a spring effect. Very very cool. I really love the idea of Inductrack and I wonder why we don't see more of it today... A Transportation Enthusiast 02:30, 30 June 2006 (UTC)

"why we don't see more of it today" - probably because its about 6 years old, and its a nitch application. I would imagine that most of the applications for it are large projects that usually are run by the government. And we all know who would win the race between the tortoise, the hare, and the government. Fresheneesz 10:23, 30 June 2006 (UTC)

Yes, I can see where something so new wouldn't be applied right away, especially in a gov't-dominated domain like transit. But I guess I'm surprised I haven't heard more about it before now. I would think it would have merited huge headlines given it's enormous promise. I wonder if there are any "gotchas" we don't know about... A Transportation Enthusiast 14:49, 30 June 2006 (UTC)

I think the reasons are many. First is probably a general fear and distrust of maglev. Which is based on information that says maglev requires a lot of advanced technologies that are not yet perfected, and requires high voltage electricity to maintain intense magnetic fields both of which may cause cancer and genetic damage. But it may be less conspiratorial, it may just be that Inductrack has some difficulties that will take time to overcome.

For example, you described it as a "spring effect", which is probably very accurate. Like other springs, Inductrack's "spring" has a natural equilibrium and when it's compressed, it will spring back past the point of equilibrium causing oscillations. Which is why there are shock absorbers when vehicles use springs for suspension. Inductrack will have to do something to dampen the oscillations too. Either by adding weight to the car with hydraulic shocks maybe or by adding active manipulation of the magnetic fields on the track. Inductrack's springiness varies with speed, from a very loose spring at low speeds to a very taught spring at high speeds. So at low speeds the pod will bounce, and at high speeds the pod will vibrate.

I think another problem that Inductrack will have to deal with is the need to still provide a lot of electricity to the pod for propulsion, more electricity for propulsion at 30 MPH than if the pods had hard wheels rolling on a hard track. Because they call it "passive", the assumption is that it requires less energy. You've said yourself that the levitation portion requires "no direct power input", but that's not necessarily true. The coils require no external electrical source, but there IS power input by virtue of magnets being pushed past the coils. You don't get levitation for free just because the electrical energy is induced from some other form of energy. If the movement induces the electricity, then the movement is going to require more energy input. This is mostly a marketing hurdle though.

Based on a cursory introduction to Inductrack, I think it is a better form of maglev for human transport than active maglev. I don't necessarily think maglev is the best suspension system for an urban commuter transit system. It's probably better suited for high-speed rail between Los Angeles and Las Vegas. --JJLatWiki 16:42, 30 June 2006 (UTC)

In addition to JJLatWiki comments, it would seem to me to be an expensive overkill. First you have expensive permanent magnets. Second you have lots of copper in the windings. Hard rubber tires that neither steer, propel or brake riding on smooth steel sounds a lot simpler, and last much longer than on automobiles. This should be good for at least 75mph, which is about as fast as a normal car ever goes in the US. Few PRT proposals exceed this speed. pstudier 03:53, 1 July 2006 (UTC)

Well, I agree to a point. Maglev in general would seem to be overkill for a PRT system. But this is such a simple and elegant form of Maglev that it would seem to be a candidate. Consider a PRT system that is already using LIM: there is already a lot of infrastructure required there, so how much more would it be to go to Inductrack with built in LIM propulsion (something that the SciAm article says is quite possible)?

There would be several advantages to this design:

• smoother ride
• higher top-end speed (not that a small system would need it, but if you're talking about a system that could expand into less densely populated areas, higher top end speed might be useful in the long term).
• fewer moving parts, meaning lower maintenance costs. Sure, there'd still be wheels, but they'd only operate at 5kmh and lower. The wear on these wheels would be minimal.
• possibly lower stresses on the guideway, since the load would be distributed along the whole length of the magnet array instead of just at the wheel contacts.
• increased safety - Inductrack would seem to be more fault tolerant than wheels on track
• quieter - maybe.

Furthermore, since PRT vehicles are so much lighter than trains, the same effect might be achieved with cheaper materials.

There would still be questions... JJLatWiki raised some earlier (i.e. the possible need for shock absorbsion). In addition to that, how inefficient is Inductrack at low speeds? What would be the crossover speed at which Inductrack is cheaper to run than wheels? If the crossover speed is high, then it might not be worth it for PRT; OTOH, if it's low enough to at least make Inductrack competitive with wheels on rails at PRT speeds, it might be worth consideration. Maybe Malewicki is onto something here... A Transportation Enthusiast 07:41, 1 July 2006 (UTC)

The two main figures malawiki claimed about Inductrack is a magnetic drag equivalent to .003 crr - which is decently small. The other is that the vehical would start levetating (off its wheels) after being accellerated to above 2 mph - which is very decently slow.

One problem I see with wheels is in switching. Skytran proposes under-hanging vehicles, and so when switching one wheel would have to roll over a gap (that allows the support to hang down). I can see it not being very much a problem at all, but it would be a point for potential failures to happen. Also, wheels could use linear propulsion, but why not go all the way maglev if you have that? So if wheels don't have linear propulsion, then it needs a moter, drivetrain, suspension, steering mechanisms. Linear propulsion with maglev avoids all of those things. Instead of having a vehicle with 2 moving parts, the door and the AC unit, you would have a vehicle with scores of moving parts, many of which need to be kept lubricated somehow. This means lots of maintenance, keeping wheels greased, replacing burnt moters, etc.

I doubt any of you have read my report on SkyTran, but its main benefit was NOT installation cost. Its main benefit was operating cost (and operating benfits). Spending fully 10 times the amount of money to build a SkyTran system hardly makes a difference in the benefit after 30 years. I calculated that at $1 mil per mile, SF would save $28 billion, and at $10 mil per mile, SF would save $26 bil. 2 billion dollars is alot, but 7% isn't. I guess my point is here, don't expect 10 times less benefit when increasing system building cost by 10 times.

Also, I disagree about the statement "at high speeds the pod will vibrate". Inductrack will repell the pod at increasingly higher force, however, the force of gravity will stay the same. This is not an F=kx situation. Harmonic vibration will not occur. The pod will "bounce" at low speeds, but will "bounce" less at high speeds. While the frequency should be higher, the amplitude of the "bouncing" will be much less at high speeds - as the levetation will act more like a magnetic wall than a magnetic spring. Fresheneesz 09:03, 1 July 2006 (UTC)

First let me say, I find this discussion extremely enjoyable. :-D

Fresheneesz, I see your points. I never read your full report on SkyTran, maybe I'll take a look. Your point that installation costs would be a minor factor is interesting.

It sounds as if Malewicki is very much an "idea man". His ideas seem very novel and well thought out, and his use of Inductrack is innovative. The problem, as I see it, is that many "idea men" seem to have trouble once you get beyond the idea. All indications point to Malewicki falling into this category - great visionary, not-so-great implementor. This is not intended to be an insult - by and large the visionary is a much more important role than implementor. But you do need both to succeed. So, maybe all UniModal needs is a engineer/business manager to take that idea and produce a product. For now, it's just a really (really!) interesting concept. A Transportation Enthusiast 04:24, 2 July 2006 (UTC)

One interesting thing I found is that - for inductrack - the magnetic drag is supposed to *decrease* as speed goes up (above the transistion speed). So perhaps its just as good to use tires at speeds of around 20 or 30 mph, but at 100 or 500 mph, you'd probably do much better with inductrack. Fresheneesz 18:46, 2 July 2006 (UTC)

I also just found an article that says that EDS maglev (electro dynamic systems?) also have high drag at low speeds but near 0 magnetic drag at high speeds. Fresheneesz 18:49, 2 July 2006 (UTC)

That could explain why it is in the Unimodal design then. Stephen B Streater 19:04, 2 July 2006 (UTC)

[edit] Wow

Has anyone here actaully taken a look at the practical implications of the design? For one thing, if you had an old grandmother who took a whole minute to get out of her 'pod,' a massive queue would form behind her. For another, the stop-and-go type movement makes levitation not worth the cost (the wheel would be in contact with the rail most of the time). Ask yourself: why not use a bloody _tire_, like the French underground system? The answer, of course, is "because mag-lev sounds cooler." This is scince-fantasy, and if it isn't deleted outright it needs to be cut down significantly. Therealhazel 20:05, 9 July 2006 (UTC)

The "old grandmother" problem is true of other forms of transit as well. If it takes an old grandmother a minute to disembark a train, then the entire train waits, and trains behind might need to wait too. This problem is not unique to PRT.

True, but trains have multiple, wide doors opening out onto a wide platform, not a single pod opening on to a narrow walkway. You could always have a whole platform set out at pod-level at each station... If you wanted to make the project more expensive than the Seattle Monorail, of course.

Besides, the article doesn't mention how many stations would be included: you have to go to the website for that. There are a number of points that should be included for the article to meet basic standards.Therealhazel 23:33, 12 July 2006 (UTC)

As for the levitation, it is my understanding that Skytran was intended for use over regional distances, so that the levitation would allow for higher speeds over longer distances. And the maglev being proposed is a passive form that does not require the level of active infrastructure that typical maglev requires. I'm not saying maglev is necessarily practical (I don't know all the technical details so I can't make a judgement) but the idea of using this type of passive maglev for a system such as this is not as fantastic as it looks at first glance. A Transportation Enthusiast 22:46, 9 July 2006 (UTC)

The old grandmother would only delay one station. In all PRT designs that I know of, the stations are off the main line. pstudier 01:20, 10 July 2006 (UTC)

Ah, that would cut down on the queue problem, but would seem to require a much more complicated system than that depicted in the article. Infact, the article lacks any mention of a switching system...

Of course, slowing a pod down to enter a station would slow down all the ones behind it, unless you used an off ramp-like length of track before the station to slow the pods down. That seems somewhat inconvenient in a city environment. Of course, you could always just pull a 5g slowdown in a few seconds, but I don't think the afore-said grandmother would deal too well with that... Of course, the website shows a very short "deceleration line," with what appears to be a 45 degree slope. Talk about a roller coaster ride... The skytrain site FAQ says: "All these issues are well thought out." They just can't be discussed on the site.

Also, have you considered the problem of merging back onto the main track? A freeway gives you quite a long time to accelerate and merge into traffic, but it can still be a hair-raising experience. Coordinating a busy merge with only one switching point seems almost impossible. Railways can do it because they have very long distances between trains. How will 'UniModal' do it?

I'm just saying that unless questions like this can be answered using sourced information, the article can't really be considered very practical. Therealhazel 23:33, 12 July 2006 (UTC)

So you're saying that since you think the idea won't work, we should cut down the article, or delete it. Good thinking.... I'd give a detailed explanation of every point you got wrong, but you can use your imagination after pondering the above comments. Fresheneesz 07:33, 11 July 2006 (UTC)

"How will 'UniModal' do it?" - Unimodal would have accel and decel tracks to and from the main line. Pods would coordinate themselves to fit into the right spots when merging onto the main line. This wouldn't even be very hard for a human at the proposed 72 foot spacing. Fresheneesz 07:28, 13 July 2006 (UTC)

[edit] Gross misunderstanding

Under the header above, Therealhazel seems to have misunderstood about every aspect of PRT and SkyTran's design. Stop and go? Long queue? SkyTran plans on an *average* of 30 second embarkation times - putting a full minute in the area of a moderate to frequent occurance. Wheel would be in contact most of the time? Are the pods stopping every two seconds?

I hardly think Therealhazel is some sort of daft idiot - instead I think it is a failing of our article to provide the neccessary info in an easily understandable way - at least in part. I wonder if I could stimulate discussion on how we could better present the idea of SkyTran. Fresheneesz 07:40, 11 July 2006 (UTC)

All you have to do is show the measurements from the real-world urban PRT installations. Oh, wait... We don't need to "better present the idea of Skytran", this article does a pretty good job. Therealhazel just needs to read the main PRT article, since these are generic issues. Just zis Guy you know? 08:48, 11 July 2006 (UTC)

Except for his sarcastic mantra, I agree with JzG that the understanding of how UniModal would avoid "stop-and-go movement" is the responsibility of the main PRT article. Which also means that it is the reader's responsibility to read the PRT article. Like a perpetual motion machine or the impossibility thereof, even if you think the theory is wrong, you must comprehend the underlying theory upon which the development is based before you can debate the development. It appears to me that this reader just did not read and/or comprehend, but maybe doesn't accept, the PRT concept. --JJLatWiki 16:54, 11 July 2006 (UTC)

Maybe we can paraphrase from the PRT article, we can't assume that a reader will want to dig through every topic they don't know about in order to understand the topic they do want to know about. And JzG, give it a rest will you? Fresheneesz 00:04, 12 July 2006 (UTC)

Possible, but I'm planning to do some more work on PRT first. It may be easier to link to the PRT article instead. Stephen B Streater 16:26, 12 July 2006 (UTC)

You'll have to explain at least maglev and Inductrack too. We don't paraphrase those concepts. And this is only one question? Are we looking for a solution to a problem that doesn't exist? --JJLatWiki 17:07, 12 July 2006 (UTC)

Maybe. Maybe its just his problem. Fresheneesz 20:48, 12 July 2006 (UTC)

How bout we just put some note up about how this page requires knowledge from the PRT page? Fresheneesz 07:16, 13 July 2006 (UTC)

Or we could ask the developers to come up with some way of linking the text, so when you see terms like personal rapid transit or inductrackyou can click on them and find out what they mean. I don't think this would be a big change... Just zis Guy you know? 21:36, 13 July 2006 (UTC)

Thanks for the useless comment JzG. I think i'll just put it up on my own. Fresheneesz 00:04, 14 July 2006 (UTC)

Well there's something new: a sarcastic, condescending comment from JzG! A Transportation Enthusiast 03:26, 14 July 2006 (UTC)

[edit] A Series of Interesting Points

You may wonder about my sceptisicm, but I think it's pretty clear that unrealistic claims must be questioned. Our friend Fresheneesz claims a minimum "13900% return to investment" on his website dedicated to skytran. That makes my BS detector react quite strongly. In that vein, here are 5 points that illustrate how seriously whacked this proposal is.

First of all: The site makes it clear that pods won't fall to the ground if power is lost, but it fails to mention a small side-problem: you're in a little metal box thirty feet above ground with no way out, having just undergone extremely rapid deceleration thanks to the patented hydraulic disk brake. If power will be out for a long time, the city would have to have the city send dozens of cherry-pickers along the line to rescue people. Adding a walkway to the track that meets american safety standards would add significant weight to the system, violating the cost-reducing assumption that the support posts are "standard utility poles." Of course, one could always use the "small battery idea." Unfortunately, power to induction motors is supplied through the track, not by the pod. Besides, communications to the main computing center would be required to get the pods to their emergency destinations, as well as juggle empty ones out of the way. Assuming your "small battery" can last long enough, communications loss would leave people stranded anyway. That's why every ground transit system (including the chunnel) has openable doors and a walkable path to safety. According to Freeze's first comment on this page, Skytran would have neither.

Secondly, Popular Mechanics claims that levitation can be achived at speeds of "1 to 2kph." However, both Scientific American and "Science and Technology give much higher lift-off figures (22kph and 100kph respectivly). http://www.llnl.gov/str/October04/Post.html Notice that the source agency quoted in the article actually built a test track, unlike our boys at Skytran.

Third: The braking issue. Using data from the Skytran site, I've found out that an object decelerating from 100MPH in 55 feet (about the length of the braking zone pictured) would be subjected to 6Gs. That's exactly the emergency braking rate of this system, which according to the site will be used only in emergencies. A car undergoing "hard braking" in order to slow down does .4Gs, and you wouldn't want to do more than that on a public transport system, as you can't make sure people are wearing their seatbelts. At .4Gs, the system would take 835 feet to stop. That's 1/3 of a mile of acceleration and deceleration "branch line" track, _plus_ the space required for the two stations and the storage area (100-200 feet). That's .37 miles for each station, far more than depicted on the sample "route map," which doesn't take any of that into account. Here's the site: http://www.skytran.net/09Safety/02sfty.htm.

Fourth: Drive System. Is there a second system for forward motion? It is mentioned only in passing on the website, and "inductrak" simply provides lift in exchange for drag. The test model was "launched mechanically at the beginning of the track at speeds exceeding 10 meters per second." (http://www.llnl.gov/str/Post.html) The model went less than 20 meters before settling back down on its wheels. Not only is "a power source needed to accelerate the cart to its operating speed," acceleration must constantly be supplied to resist both atmospheric drag and drag caused by the levitation coils. The proposed NASA system used to launch rockets would use a rocket booster itself, or, according to the .gov site: "will interleave powered drive coils with passive levitation coils." The required "powered drive coils" have the same problem that Inductrak gets around, namely shielding, cost, and increased weight on both the track and pod. Having to use stator packs all along the track would increase the weight and cost significantly, making costs equivilant to regular mag-lev systems. So much for "1 million a mile..." The site mentions an "electric induction motor," but does not show one in the diagram. Only the Inductrak system is shown, although on an FAQ side-site a "shrouded propeller driven by a gas turbine" is mentioned. Of course, you could always use little jets. That should go over well with the public.

Fifth and lastly: The site has sub-standard design and writing. No section of the site is written with investors in mind. These people don't seem to take their business very seriously, as the vast majority of their site is sensationalistic and targeted to visionaries, not venture capitalists.

Anyway, I've devoted far too much time to this article. I intend to take no further part in the discussion, as it's gotten far too heated for civility anyway, but I wanted to leave you all with some things to chew on (or attack while foaming at the mouth, depending on the person :D ). I'll check back to see what's happened in a month or two. Have fun, all!

Therealhazel 01:31, 13 July 2006 (UTC)

In response to each point:

• Point 1: the cherry picker: the point is that the levitation system will not fail catastrophically in the event of a severe failure. Contrast this with a superconducting maglev: if power fails the vehicles come crashing into the track at speeds. This, however, does not in any way imply that such failures will be common in Skytran. PRT skeptics like to bring up the "cherry picker" argument in debates, because it instills fear in the uninformed, but the fact is: checked-redundant design would prevent the "cherry picker scenario" for all but the most rare and catastrophic failures. So the benefit of Inductrack is: even when an incredibly rare set of simultaneous failures cuts power to the track, this type of failure would not cause the vehicles to crash down onto the track. And in the event of such a catastrophic failure, a cherry picker is certainly preferable to body bags.
• Point 2: levitation speed: you should re-read the source you cited: "As long as the train is moving above a few kilometers per hour—a little faster than walking speed—it is levitated 25 millimeters above the track’s surface." I don't know where you got the 100km/hr figure. I also checked Scientific American, and saw no mention of a 22km/hr levitation speed.
• Point 3: accel/decel track: it is not clear how Skytran handles acceleration/deceleration off the main track. Some pictures I've seen seem to show a side track alongside the main track, which may allow for the required accel/decel zones. The use of side tracks might not be such a big issue for Skytran due to its narrow vehicle profile. But honestly, I don't know how they handle it.
• Point 4: the drive system: from what I've read, integrating propulsion into Inductrack is straightforward, by inserting electromagnets at regular intervals on the track. This certainly introduces some complexity, but I don't see how you can conclude that it would push costs to traditional maglev levels. What makes other forms of maglev so expensive is the complicated control systems required to maintain accurate levitation gaps, as well as to protect against a power failure which would be catastrophic at speeds. Neither of these concerns applies to Inductrack. So I'm no expert, but my impression is that adding propulsion to Inductrack does not dramatically increase complexity or cost, at least not to the degree that you are implying.
• Point 5: "targeted to visionaries": Malewicki does seem to be lacking in the area of business and marketing. I've said this before: he seems to be an "idea guy" who is great at coming up with new and innovative ideas, but is not so great at moving from idea to product. But his lack of business acumen does not necessarily invalidate his ideas and designs.

A Transportation Enthusiast 04:51, 13 July 2006 (UTC)

"having just undergone extremely rapid deceleration thanks to the patented hydraulic disk brake" - pods would't brake in the event of a power failure. Solves that problem.

"power to induction motors is supplied through the track" - Simply incorrect, the linear propulsion is powered on each vehicle.

"the source agency quoted in the article actually built a test track" - the test vehicle levetated at 22 kph, but LLNL predicted that at the dimensions of a full sized track and vehicle, 1 to 2 kph could be reached. This would be because of different dimensions of the system, although I'm not sure on the details - A source for that is already in the text I believe.

"you can't make sure people are wearing their seatbelts" - Why not...?

"car undergoing "hard braking" in order to slow down does .4Gs" - I highly doubt that. I looked for a source, to no avail.

"The site has sub-standard design and writing." - No argument there, his site sucks. I tried to suggest improvements but that never panned out. His more business oriented site is the UniModal.com one - which I also think is pretty bad. Fresheneesz 07:11, 13 July 2006 (UTC)

0.4 g's

CARS

Normal Hard Braking

835 feet

11.4 seconds

That's straight from the unimodal site (http://www.skytran.net/09Safety/02sfty.htm), the red, white and blue example spreadsheet. The higher figure below that is the kind that gives people whiplash (especially Little Old Ladies, who are our lowest common denominator for design standards), so it's safe to assume that skytrain won't try to decelerate much faster on a regular basis. That means that point 3 is still unanswered.

It also says specifically in the FAQ that the braking system will cut in during a power failure. Of course, with the wheels not touching the track, that might be somewhat of a problem... They don't explain that bit. One would have thought that a braking system on a maglev track would have to be somewhat more complicated than a regular brake disk.

"the linear propulsion is powered on each vehicle." Meaning what exactly? A seperate power unit on each pod? Wouldn't that raise the costs significantly? The projected costs seem to be based on using regular utility poles. With the addition of a seperate motive track and the power transmission required, you'd have to use a special pole. Even if practicality didn't require it, the government would!

As for the seatbelts, do you know how much money is spent with little effect every year in an attempt to get people to wear them in cars? You must _always_ assume stupidity in your customers, because if one person gets thrown out the windshield of a moving pod because they're too dumb to wear a belt, you're facing huge lawsuits.

The cherrypicker argument is still valid. No matter how unsafe private transportation on highways is, the government insists on the highest safety standards for public transportation. It doesn't matter if is very unlikely, it would _not be allowed_ in any design sponsored by the government.

In any case, point 3 is the most telling. Not considering how the units are expected to speed up and slow down without interfering with the pace of the network is an unforgivable design flaw. It can't just be explained away in an article of this size and complexity by saying "they've probably got a solution"

One more thing. Have you all noticed that only 1 or two pages link to this one? Normally, a page with that number of links would be little more than a stub.

(Sorry for the poor spelling and formatting--I'm rather tired, and will fix it tomorrow)

Therealhazel 08:24, 25 July 2006 (UTC)

If your point is that Skytran is a concept with many questions, well, I don't think any of us would disagree. That's why it's labelled a "hypothetical concept" with "no prototype". As for point 3, I don't know the answer. Maybe there is none. But regardless, it's original research on your part. Perhaps, as I indicated in my note, there is a longer section of parallel track for speeding up and slowing down. Or maybe the control algorithm allows for the gaps necessary for speeding up and slowing down. This might limit either speed or capacity in dense areas, but it would be a valid approach. Or, perhaps, during busy times when there are few gaps in the track, the speed of the pods could be slowed so that large gaps are not required for merging/diverging to a station. This would imply slower speed but not necessarily lower capacity (if time headway is maintained) while allowing for vehicles to merge without large pod gaps.

All of this is speculation, but no more speculative than your statements. The point is, Skytran is a private entity and does not provide all of these details. We can debate in circles all we want, but it's not going to get us anywhere. A Transportation Enthusiast 15:07, 25 July 2006 (UTC)

Also, Therealhazel, is this you who deleted the Inductrack link to this article? If so, then I would question why you would delete a link anonymously, then argue that the linked article is insignificant because few link to it. A Transportation Enthusiast 15:34, 25 July 2006 (UTC)

If that anonymous deletion by the user at IP: 134.173.75.23 was not Therealhazel, there's an interesting set of coincidences: 1) The IP belongs to the Claremont Colleges, of which Pomona College is a member, which Therealhazel attends, 2) on June 9, both IP 134.173.75.23 and Therealhazel made edits to Teflon coated bullet. Maybe Therealhazel didn't mean to make the Inductrack deletion surreptitiously though. FYI, Therealhazel has also deleted similar links from maglev train and the mathematical use of unimodal. So clearly, Therealhazel has an interest in orphaning UniModal to the greatest extent possible, and then almost revelling in it: "One more thing. Have you all noticed that only 1 or two pages link to this one? Normally, a page with that number of links would be little more than a stub." --JJLatWiki 17:55, 25 July 2006 (UTC)

"Have you all noticed that only 1 or two pages link to this one? Normally, a page with that number of links would be little more than a stub." I HAVE noticed that, and it seems to be getting worse. But are you implying that the article should be shortened INTO a stub? Because it seems to me that when an article is identified as a WP:STUB, it's meant as motivation to LENGTHEN the article. Or, are you suggesting that we find other articles to link into this one? --JJLatWiki 21:22, 25 July 2006 (UTC)

Re: the "Normal hard breaking" "straight from the unimodal site" - I thought you meant "normal" emergency braking that people do in an emergency (like when they're gonna crash). I'm sorry, I misinterpreted your words. However, "normal hard braking" of .4 G's is a *comfortable* rate. Which is about the rate that skytran proposes to accel and decel at. Emergencies aren't supposed to be comfortable, they're supposed to save your life. Not to mention that such an emergency most likely would never happen in a properly designed PRT system. There goes point three.

"It also says specifically in the FAQ that the braking system will cut in during a power failure." - look closer, this is the quote *I* found:

"If power fails, vehicles can continue to their destination, or for at least many miles before stopping at a portal." - [5]

"more complicated than a regular brake disk" - you gonna trust your life to a regenerative brake? Hybrids still have emergency brakes. Regenerative brakes are used *most* of the time - unless your life is in danger.

"A seperate power unit on each pod? Wouldn't that raise the costs significantly?" - You need linear motors either on the track or on the vehicle, one or the other. Personally I think having them on the vehicles reduces the number of LIMs needed.

"do you know how much money is spent with little effect every year in an attempt to get people to wear them in cars" - how bout this?: Don't close the doors until the passangers put on their belt. Also, companies are legally protected from the idiocy of their customers, especially if they put up a warning like "SkyTran is not responsible for death or injury sustained by persons who remove their seatbelt enroute."

"The cherrypicker argument is still valid." - I already mentioned why this isn't an issue, vehicles aren't supposed to stop in a power outage - power is on the pods as far as i know. Fresheneesz 23:11, 26 July 2006 (UTC)