British Rail Class 23
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The British Rail Class 23 Bo-Bo Diesel-electric locomotives (so-called 'Baby Deltics') were a ten strong class of locomotives built by the English Electric Company in 1959. They were numbered from D5900 to D5909. The power unit used a Napier Deltic T9-29 9 cylinder engine of 1100 hp driving an EE generator, which powered the four traction motors.
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[edit] Usage
After acceptance trials at Doncaster, the locos were based at Hornsey. It had been BR's original intention to work the locos across London on the widened lines but they were found to be too heavy. The first of the class was stopped at Vulcan Foundry whilst EE tried to reduce the weight but this could not be completed to a satisfactory standard.
The locomotives were put to work on King's Cross outer suburban duties such as the Cambridge Buffet Express as well as services from Kings Cross to Moorgate. The locomotives were later banned from Moorgate because of excessive exhaust smoke in the tunnels.
[edit] Problems
It wasn't long before serious problems were being found with the class. Many engines seized because the shaft driving the auxiliaries from the engine snapped and whipped round rupturing coolant hoses. Other lubrication problems caused seized pistons and cracked cylinder liners. By around 1963, all the locomotives had gradually been moved to Stratford Depot as they failed and were added to the line in store, pending a decision on their future. By this time the locos were based at the new diesel maintenance depot at Finsbury Park.
[edit] Modification
It was decided by BR and EE to carry out a program to refurbish the class and modify the engines with new parts designed by the engine manufacturer. The locos also had modifications to their nose ends, losing the gangway doors and headcode discs in favour of a central roller blind headcode box. The livery also changed to two tone green with grey roof to mimic that of their larger sisters so they looked every bit a 'baby deltic'. The locomotives gradually returned to traffic and became very reliable in traffic except for ongoing coolant system problems.
[edit] Withdrawal
They were unable to redeem themselves however as BR had drawn up the National Traction Plan to rationalise the number and types of diesel locomotives in traffic and they were an obvious target being only a ten strong class. The locos were deemed as non standard and withdrawn between 1968 and 1971. The last two locos in traffic on revenue earning service were D5905 and D5909. Several of the class received full yellow ends whilst still in two tone green, a couple even carried the new double arrow BR symbol. D5909 was the only locomotive to receive the full rail blue livery. D5901 was transferred to the departmental fleet of the Railway Technical Centre in 1969. It worked test trains to and from the RTC until 1975 when it was replaced by a Class 24. The loco was cut up in 1977, still carrying two tone green livey with a grey roof and small yellow warning panel.
[edit] Technical details
- Introduced: 1959
- Weight: 73 tons 17 cwt
- Engine: Napier Deltic T9-29 of 1,100 bhp
- Transmission: Electric, four English Electric traction motors
- Maximum tractive effort: 47,000 lb
- Driving wheel diameter: 3ft 7in
- Coupling code: Blue star (electro-pneumatic)
- Train heating: Steam generator
[edit] The Super-deltic
There were once plans for a "Super-deltic" of 4,400 horsepower and it may be that the Class 23 was a testbed for the proposed power unit. The T9-29 engine was turbocharged and a pair of 18-cylinder engines of the same type would have delivered 4,400 hp. The Super-deltic was never built and lies in the realm of "what might have been".
[edit] Sources
Ian Allan ABC of British Railways Locomotives, summer 1966 edition
[edit] Models
The Class 23 "Baby Deltic" has been made as a kit from Silver Fox models but has yet to be made as a ready to run 00 gauge model
