German railway signalling
From Wikipedia, the free encyclopedia
Railway signals in Germany are regulated by the Eisenbahn-Signalordnung (ESO, railway signalling rules). There are several signalling systems in use:
[edit] History
[edit] Reichsbahn
Originally every rail company had its own signalling system. After these companies were transferred to the ownership of the national rail company Deutsche Reichsbahn a common signalling system was created.
Main signals allowed the train to proceed or not. These signals were semaphores. They had at least one arm which meant "Stop" when aligned horizantally, "Proceed" when aligned diagonally. Up to two adittional arms could be mounted for different routes. They were mounted below the "stop"-arm. They are aligned diagonally when the route diverges from the main route and aligned vertically to show, that the main route is used.
At night, a horizontal arm showed a red light, a diagonal arm showed a green and a vertical arm showed none.
Signalling the route was changed about 1930 to signalling the speed. The third arm was removed and the green light of the lower arm changed to yellow in 1948. This system is still in use.
First light signals came in use, but were not widely spread when the country was divided in 1948. These signals showed the night aspects of the semaphore signals and could not be considered as an own signalling system.
Only the S-Bahn systems (Berlin, Hamburg) were equipped with newly designed light signals, the Sv-System.
[edit] post WWII (Separation into two Germanys)
Two new Companies were founded. The Deutsche Bundesbahn in West Germany, the new Deutsche Reichsbahn in East Germany. The Reichsbahn kept the name of the old Reichsbahn, to keep infrastructure and the right to operate trains in West Berlin. Both companies had their own regulations from then and they were diverging until 1990 when the country and the rail companies were reunified. One get get an idea which signals existed before the separation if one compares both regulations.
[edit] West
The Deutsche Bundesbahn mainly kept the H/V signalling. Nevertheless the signals changes their design over the years. One very early change was the inclusion of shunting signals (Sh, Schutzignale) into the main signal's head. This effected mainly exit signals. These signals showed two red lights to disallow any train or shunting movements and a red-white-white combination to allow shunting movements only. Later the backup signal aspects (Zs1, Zs7, Zs8), which had their own head, were also merged into the main head. The new signals had a cosmetical enhancement too, they were all rectangles now.
The signalling system didn't change much to allow Gleiswechselbetrieb, which means, the wrong track (of two) can be regularly used. Only a new aspect (Zs6) was needed to inform the driver about using the wrong track.
Several minor experiments for new signalling systems were made, but only one survived. A single line (Augsburg - Donauwörth) was equipped with Sk-signals. The signals still exist, and the new common (West and East) signalling system were developped from these.
[edit] East
The Deutsche Reichsbahn adopted a new signalling system from the OSShd, a supranational organization of railways, mainly "Eastern" railways. H/V light signals as built in the West existed at some places were the were mounten before the war.
[edit] Reunification
Several signalling systems and two regulations existed now within the reunited Germany. The regulations are contineously merged to form a single one. This process is still in progress and will keep during the next years. Most of the network will change to centralized signal-boxes, during this process a complete line generally changes to the new common Ks-System. But old signalling systems are still installed on few new lines for several reasons, even new semaphores are produced, mainly for spare parts. Currnetly no newly developped signalling system is in sight, the current system seems adeqate for today's operation. The next step will be a system without signals anyway, as current developments show: LZB, ETCS
[edit] In Comparision to other Countries
...
[edit] Home signal/distant signal (H/V)
The most common system is the H/V (Hauptsignal/Vorsignal) system which consists of home signals and distant signals. Depending on the technology used in the signal box, these signals may be indicated by semaphores or light signals. The light signals show the same light patterns the semaphores show at night.
 |
 |
 |
[edit] Hp 0: Stop
A home signal shows Hp 0 by a horizontal arm of the semaphore signal or one red light or two horizontal red lights. The signal requires the driver to stop in front of the signal.
Usually, Hp 0 is protected by a 2000 Hz magnet of the PZB train safety system which triggers the emergency brake, should the train pass the signal.
 |
 |
 |
[edit] Vr 0: Expect stop
A distant signal shows Vr 0 by a yellow disc or two yellow lights (the right light is above the left light). This signal indicates that its home signal shows Hp 0. As the signal is placed at braking distance from the home signal, the driver needs to apply the brakes immediately to stop the train before reaching the home signal.
Vr 0 is usually accompanied by a 1000 Hz magnet of the PZB train safety system which first triggers an accustic signal that must be acknowledged by the driver and then supervises the braking. If at any point the system detects that the train may not stop in time, it triggers the emergency brake.
 |
 |
 |
[edit] Hp 1: Proceed
Signal Hp 1, indicated by the raised arm of the semaphore or a green light, allows the driver to proceed at the speed indicated in his schedule.
 |
 |
 |
[edit] Vr 1: Expect proceed
Vr 1 indicates that the home signal shows Hp 1. On a semaphore, the yellow disc is turned horizontal, while light signals show two green lights with the right one above the left one.
 |
 |
 |
[edit] Hp 2: Proceed at reduced speed
If both arms of the semaphore point up, or a green light is show vertically above a yellow light, the train may proceed at reduced speed. Unless another speed is indicated by additional signals, the train must obey a speed limit of 40 km/h. Hp 2 usually indicates that the next block is free, but that some switches are turned in a way that does not allow passing them at full speed.
 |
 |
 |
[edit] Vr 2: Expect proceed at reduced speed
Vr 2 orders the driver to slow the train to 40 km/h prior to reaching the home signal showing Hp 2. Other speed limits may be indicated by additional signals.
[edit] Hl Signals
Hl-signals were used in East Germany. The upper part of the signal is a distant signal, the lower part is the main signal. Signals can also be used without the main aspect or without the distant aspects.
[edit] Hl distant aspects
There is a green and a yellow light. Both can be flashing. So there are four different aspects:
Yellow: Expect Stop
Flashing Yellow: Expect Proceed with 40 km/h or 60 km/h
Flashing Green: Expect Proceed with 100 km/h
Green: Expect Proceed with maximum speed
[edit] Hl main aspects
There is a yellow and a red light on the signal, and additionally a bar with four green and four yellow lights below the signal.
No Light: Proceed
Red: Stop
Yellow: Proceed with speed limit
If there is a speed limit (yellow light) it is shown by the green or yellow bar:
No bar: 40 km/h
Yellow bar: 60 km/h
Green bar: 100 km/h
[edit] Kombinationsignale
After the reunification 1990 a new signalling system was designed to have a common system in East and West. While West Germany uses signals which simply show the night aspects of the semaphores, East Germany designed new light signals similar to those in other Eastern European countries. So usually, new built signals are Ks signals. That is not obligatory, for the lightrail extension in Kassel H/V signals were installed even after 2000, because they didn't want their drivers being irritated. The signals have three lights green, yellow and red, and have only three aspects. There are no new signalling possibilities, all combinations can also be shown with H/V signals and vice versa. The PZB and LZB technologies are used the same way as for H/V signals.
[edit] Hp 0 Stop
One red light. The Ks system uses the same aspect for "stop" as the H/V system.
[edit] Ks 1 Proceed at given speed, expect proceed at given speed
One green light. Additionally a white number above the signal can reduce the speed. It shows the tenth of the speed limit from this signal. There can also be a yellow number below the signal showing the speed limit from the next signal. It is shown only if the speed limit at the next signal is lower than here. If such a yellow number is shown, the green light is flashing.
[edit] Ks 2 Proceed at given speed, expect stop
One yellow light. Speed can be reduced from here as described for Ks 1.
[edit] Additional signals
A number of additional signals provide additional information to the driver or modify the meaning of other signals. They are named "Zs" (Zusatzsignal = Additional signal) plus a number. Names are different in East and West. Names shown here are the names used in West Germany
[edit] Zs1 Ersatzsignal
Ersatzsignal = Backup signal
Three white lights aligned as a triangle or one flashing white light.
Meaning: It is allowed to pass this signal with a maximum speed of 40 km/h until the last switch, after last switch with regular speed.
This signal is used, when a signal fails due to several reasons. One possibility is that one ore more bulbs don't work, and the wanted aspect cannot be shown. So a signal which should show Hp2 (green + yellow, proceed with 40 km/h) could have a broken yellow bulb. It would show Hp1 (green, proceed with maximum speed). So it must show something else. Another possibility is that one of the automatic checks fails. A switch or track would not give information about its state. Then it must be manually checked that the tracks and switches are free/in right position. Then the signal Zs1 can be given.
[edit] Zs2 Richtungsanzeiger
Shows one single white letter indicating direction. The letter is usually the initial letter of the next station or the next major station.
This signal does not give any specific command to the driver, as driving to the wrong dircetion is not dangerous by itself, but he should ask if he is led to the wrong direction by intention or by error, so the main signal could be switched back to red and the direction can be changed.
[edit] Zs2v Richtungsvoranzeiger
Shows one single yellow letter.
Meaning: Expect Zs2
[edit] Zs3 Geschwindigkeitsanzeiger
Shows one white number indicating the tenth of the speed allowed from this point.
Usually used in combination with main signals. Zs3 are used for speed limits when leaving the main track via switches. General speed limits for all tracks are posted using Lf-plates.
[edit] Zs3v Geschwindigkeitsvoranzeiger
Shows one yellow number indicating the tenth of the speed allowed from the point where the following Zs3 signal is found.
Usually used in combination with distant signals.
[edit] Zs4/Zs5 Beschleunigungsanzeiger/Verzögerungsanzeiger
abandoned
Used to indicate the train driver, that he should accelerate or slow down to optimize the occupancy of the line. A train driver could slow down to avoid a signal showing "Stop" for himself, or accelerate to avoid a stop for the following train.
[edit] Zs6 Gleiswechselanzeiger
(East name: Zs7)
Indicates that the left (the wrong) track is used from this signal.
Used only in combination with main signals. Used on lines, where the wrong track can be used regularly.
[edit] Zs7 Vorsichtsignal
(East name: Zs11) Three yellow lights aligned as a triangle pointing down.
Meaning: Train may pass this signal but must be prepared to stop at any obstacle.
Used only in combination with main signals.
This signal is used for the same cases as Zs1. The difference is that for a Zs1 it must be checked that the path is clear where at a Zs7 the train driver must check that the path is clear.
[edit] Zs8 Falschfahrt-Auftragssignal
Three white flashing lights aligned as a triangle or a flashing diagonal light
Indicates that the left (the wrong) track is used from this signal.
Used only in combination with main signals. Used on lines, where the wrong track cannot be used regularly.
[edit] Zs10 Ende der Geschwindigkeitsbeschränkung
A black arrow with white border pointing up.
Meaning: End of Zs3 speed restriction
[edit] Langsamfahrsignale
There are several plates to post speed limits. Basically, there is a sign posting the maximum speed and if the new speed is slower than the speed before, there is a distant sign.
The Lf1, Lf4 and Lf6 plates are distant speed limits. The Lf2, Lf5 and Lf7 are speed limits. The Lf3 plate is the end of a temporary speed limit. The end of a permanent speed limit is usually not shown.
There are changes in 2007:
Lf4/Lf5 are obsolete and are being replaced by Lf6/Lf7.
A higher speed than before will now always be shown by a Lf7.
[edit] Nebensignale
[edit] Ne1 Trapeztafel
Meaning: Missing main (entry) signal
Trains must stop here, if specified in timetable. Train must wait for optical or acustical signal to proceed.
[edit] Ne2 Vorsignaltafel
Used alone or in combination with a distant signal. Meaning: This is a distant signal. (Even if there is none visible)
A main signal, shunting signal or a Ne1 will be found at braking distance. Unless a distant signal, distant signal repeater or main signal is visible, the train driver treats this signal as "Vr0 or Ks2: Expect Stop".
Every distant signal is mounted with a Ne2 plate. Distant signal repeaters or distant signals mounted in combination with a main signal do not have a Ne2 plate.
[edit] Ne3 Vorsignalbaken
Used to announce distant signals. Posted 250m, 175m and 100m before distant signal.
Generally 3 plates are used. Up to 5 can be used at bad view. Less are used, if the distance to the previous main signal is too short.
[edit] Ne4 Schachbretttafel
Checkerboard
Used to indicate that a signal is at another place than expected. This plate is posted where the signal would be expected.
[edit] Ne5 Haltetafel
Used to indicate where a passenger train should stop.
[edit] Ne6 Haltepunkttafel
Meaning: Expect Ne5
[edit] Ne7 Schneepflugsignal
Gives information how to use the snow plow.
[edit] Schutzsignale
These signals guard shunting movements. Schutzsignale = guard signals. Shunting movements do not leave a station whereas train movements do. These signals are sometimes combined with main signals, which is the reason why main signals sometimes have one red light and sometimes two. Historically, shunting movements were allowed to ignore main signals. They had to stop only at main signals with two red lights, becaus a double red light means Hp0 (stop for train movements) and additionally Sh0 (stop for shunting movements). When they were allowed to pass this signal, it showed a red and two white lights, still forbidding train movements (Hp0 + Sh1). After a change, a red always means stop for all movements. Therefore only one red light is needed. A double red has the same meaning and Sh0 is now nearly equal to Hp0 and will be replaced in most cases.
Sh0:
One or two (formerly: Two) red lights aligned horizontally
Meaning: Stop for shunting movements
This signal is obsolete and being replaced by Hp0.
Sh1:
Two white lights aligned diagonally and an optional red light.
Meaning: Shunting allowed
Sh2:
A rectangular red plate
Meaning: Stop
Used at the end of the track
[edit] Signals for electric power supply
[edit] Miscellaneus
[edit] Kennlicht
One white light Meaning: Only a white light on a signal: This signal is invalid, ignore it!
A white light on a H/V distant signal: The distance to main signal is shorter than usual (when signal hat a Ne2-plate) or this is a repeater (without Ne2-plate).
A white light in the top left corner of a Ks-Signal: The distance to main signal is shorter than usual.
A white light in the bottom left corner of a Ks-Signal: This is a repeater.
A flashing white light: Not a Kennlicht, see Zs1
Two white lights: Not a Kennlicht, see Sh1
[edit] Examples
[edit] Example 1
Entering a station (see image)
Left: Secondary line with minimum signalling
Right: Main Line with standard signalling
[edit] Example 2
The lower track is blocked. A train going from left to right cannot use the regular track. It must use the wrong track. The exit-signal of the left station shows Hp0 (One or two red lights:"Stop"), because there is no regular route to the wrong track. The signal shows also Zs8 (Three white flashing lights: "Proceed on wrong track"). The signal cannot show Sh1 ("Shunting allowed") in this case, because the ride would end at the Ra10-plate ("Stop for shunting movements"). When approaching the next station, the train will find an Ne2-plate, which substitiutes a distant signal and in this case means "Expect Stop". At the position of the entry-signal of the right station a Ne4 plate shows that a signal ist not where it is expected. Instead, the signal is mounted right of the track. This signal shows Sh1 (Two white lights: "Shunting allowed"), the train may enter the station. The signal could also stand on the left side of the track, the Ne4 plate is not used then.
[edit] Example 3
How Kennlichts are used. On the first signal you see Hp1/Vr1 as described in the H/V section of this article. On the next one you see Hp1/Vr0, which means "proceed, expect stop at braking distance". On the third one, you see a Kennlicht, which means that the main signal is switched off (=there is none). The distant signal shows Vr0 + Kennlicht, which means "expect stop before braking distance". The last one shows the expected "stop". These combinations are used, if the signals are mounted at the half braking distance.
[edit] Gallery
 Main signal switched off, dinstant signal shows "expect stop at short distance" |
 Main signal always showing Hp0, an El6 plate in the catanary and a Sh2 plate ant the end of the track |
 A Ks (main and distant) signal. Can additionally show Zs3, Zs3v and Zs7 |
 Four new Ks distant repeaters, and one old H/V distant repeater showing "Expect Stop" |
 Old semaphore and new Ks signal, both able to show "Proceed with 50 km/h" and "Stop", new signal may also show Zs1 and Zs6 |
 Ks signals mounted above track |
 Handmade Lf7. Could also be a "G2a" (the tram signal with the same meaning) |
 A Lf7 "Speed limit 20km/h", a handmade Zs3v "Expect speed limit 15km/h", and a H/V main signal showing Hp0 "Stop" |
 The situation beyond the last pictuce, speed limit still 20km/h, except for "RT-Fahrzeuge" which are reduced to 15km/h by the Zs3 plate mounted on top of an H/V main signal showing "Stop". |
