British Rail Class 23
Encyclopedia
The British Rail Class 23 were a class of ten Bo-Bo
diesel-electric locomotives built by the English Electric Company
(EE) in 1959. The power unit used was a Napier Deltic
T9-29 9-cylinder engine of 1100 bhp driving an EE generator, which powered the four traction motors. They were numbered from D5900 to D5909.
The T9-29 diesel engine was a single, half-sized version of those used in the more powerful British Rail Class 55
'Deltic' locomotives, and the overall design and external appearance of the Class 23 was also similar to the Class 55, but much shorter, leading to their nickname of Baby Deltics.
and Class 40
locomotives. The lightened locomotives eventually met British Rail's approval, but only after a painstaking weighing that involved specifying the amount of sand in the sandboxes and other precise details.
After acceptance trials at Doncaster
, they entered service between April and June 1959. They were based at Hornsey
, although at weekends were usually located at Hitchin engine shed. It had been British Rail
's original intention to work the locos across London
on the widened lines but the locomotives were found to be too heavy. The first of the class was held 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
sub-surface platforms via the 'widened lines'
(more recently, part of Thameslink
). The locomotives were later banned from Moorgate because of excessive exhaust smoke in the tunnels.
Type 2. The Type 2s were averaging 30-40,000 miles per failure, the Baby Deltic less than a quarter of this. Although they suffered problems with the cylinder liners that weren't dissimilar to those of the Class 55 Deltics, most of the Class 23's early problems were a variety of failures with the engine ancillaries. The auxiliary gearbox used to drive the compressor and cooling fans was a particular problem, suffering from vibration in its geartrain and a resonant whirling in the long drive shaft to it at particular rpm. Many engines seized because this shaft driving the auxiliaries snapped and then whipped round, rupturing coolant hoses and causing overheating.
By October 1960 the emphasis of failures had shifted from the ancillaries to the engine itself. Locomotive mileages had only reached 40-60,000 miles each, including stoppages, whilst in this 18 months there had been 44 engine changes across only 10 locomotives. Despite a generous availability of spare engines, four of the ten locomotives were out of service at the time. Four main engine problems had been identified:
In July 1961 BR suggested replacing the Napier engine with an English Electric 8SVT V8. This would however have added eight tons in extra weight, and so was rejected. EE also pointed out that the locomotives were now highly reliable in general, except when a major failure required the considerable downtime for an engine change.
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.
s so they looked every bit a 'Baby Deltic'. The locomotives gradually returned to traffic and became very reliable in traffic except for continuing coolant system problems.
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 livery with a grey roof and small yellow warning panel.
MPD at Barrow Hill (although not on display), and has now been restored to operational condition.
According to the DPS website Class 37
, 37372 has been re-engined with this T9 engine. It has yet to emerge as a working locomotive.
A photograph of the engine being started has been published in Rail Express magazine, and videos of the event are available online.
A book about the restoration of the sole-remaining 'Baby' Deltic engine has been published by The Baby Deltic Project and is available through their website.
On 5 September 2010, the Baby Deltic Project announced its plans to recreate a replica of the class. This will be achieved by way of rebuilding 37372's body and mounting it on Class 20
bogies.
Bo-Bo
A Bo-Bo or Bo′Bo′ is a locomotive with two independent four-wheeled bogies with all axles powered by individual traction motors...
diesel-electric locomotives built by the English Electric Company
English Electric
English Electric was a British industrial manufacturer. Founded in 1918, it initially specialised in industrial electric motors and transformers...
(EE) in 1959. The power unit used was a Napier Deltic
Napier Deltic
The Napier Deltic engine is a British opposed-piston valveless, two-stroke diesel engine used in marine and locomotive applications, designed and produced by Napier & Son...
T9-29 9-cylinder engine of 1100 bhp driving an EE generator, which powered the four traction motors. They were numbered from D5900 to D5909.
The T9-29 diesel engine was a single, half-sized version of those used in the more powerful British Rail Class 55
British Rail Class 55
The British Rail Class 55 is a class of diesel locomotive built in 1961 and 1962 by English Electric. They were designed for the high-speed express passenger services on the East Coast Main Line between and Edinburgh. They gained the name "Deltic" from the prototype locomotive, DP1 Deltic, which...
'Deltic' locomotives, and the overall design and external appearance of the Class 23 was also similar to the Class 55, but much shorter, leading to their nickname of Baby Deltics.
Introduction and service history
On initial completion, the first locomotives were found to weigh 3 tons over the specification weight of 72 tons. A programme of lightening was begun: some of this involved cutting circular holes into the bogie frames, and replacing steel buffer beams or roof panels with aluminium. Much of the over-weight was due to ancillary components, particularly the train-heating steam generators, being supplied over weight. To avoid waste, these components were replaced by lighter versions from other makers, but the heavier originals were then used in the Class 20British Rail Class 20
The British Rail Class 20, otherwise known as an English Electric Type 1, is a class of diesel-electric locomotive. In total, 228 locomotives in the class were built by English Electric between 1957 and 1968, the large number being in part because of the failure of other early designs in the same...
and Class 40
British Rail Class 40
The British Rail Class 40 is a type of British railway diesel locomotive. Built by English Electric between 1958 and 1962, and eventually numbering 200, they were for a time the pride of the British Rail early diesel fleet...
locomotives. The lightened locomotives eventually met British Rail's approval, but only after a painstaking weighing that involved specifying the amount of sand in the sandboxes and other precise details.
After acceptance trials at Doncaster
Doncaster
Doncaster is a town in South Yorkshire, England, and the principal settlement of the Metropolitan Borough of Doncaster. The town is about from Sheffield and is popularly referred to as "Donny"...
, they entered service between April and June 1959. They were based at Hornsey
Hornsey
Hornsey is a district in London Borough of Haringey in north London in England. Whilst Hornsey was formerly the name of a parish and later a municipal borough of Middlesex, today, the name refers only to the London district. It is an inner-suburban area located north of Charing Cross.-Locale:The ...
, although at weekends were usually located at Hitchin engine shed. It had been British Rail
British Rail
British Railways , which from 1965 traded as British Rail, was the operator of most of the rail transport in Great Britain between 1948 and 1997. It was formed from the nationalisation of the "Big Four" British railway companies and lasted until the gradual privatisation of British Rail, in stages...
's original intention to work the locos across London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
on the widened lines but the locomotives were found to be too heavy. The first of the class was held at Vulcan Foundry
Vulcan Foundry
Vulcan Foundry was a British locomotive builder sited at Newton-le-Willows, Lancashire .-History:It was originally opened in 1832 as Charles Tayleur and Company to produce girders for bridges, switches and crossings, and other ironwork following the opening of the Liverpool and Manchester Railway...
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
Moorgate station
Moorgate station is a central London railway terminus and London Underground station on Moorgate in the City of London; it provides National Rail services by First Capital Connect for Hertford, Welwyn Garden City and Letchworth and also serves the Circle, Hammersmith & City, Metropolitan Lines and...
sub-surface platforms via the 'widened lines'
Widened Lines
The Widened Lines is the name of a group of railway routes that currently form part of the Thameslink network leading from King's Cross/St...
(more recently, part of Thameslink
Thameslink
Thameslink is a fifty-station main-line route in the British railway system running north to south through London from Bedford to Brighton, serving both London Gatwick Airport and London Luton Airport. It opened as a through service in 1988 and by 1998 was severely overcrowded, carrying more than...
). The locomotives were later banned from Moorgate because of excessive exhaust smoke in the tunnels.
Technical, design and reliability problems
Initial problems with the locomotives were minor and varied, although a problem with cracking in the cylinder liner around the injector hole required the engine to be changed. By November 1959, seven engines had been changed and this reduced availability first raised comparisons with the better reliability of the British Rail Class 24British Rail Class 24
The British Rail Class 24 diesel locomotives, also known as the Sulzer Type 2, were built from 1958 to 1961. One hundred and fifty-one of these locomotives were built at Derby, Crewe and Darlington, the first twenty of them as part of the British Rail 1955 Modernisation Plan. This class was used as...
Type 2. The Type 2s were averaging 30-40,000 miles per failure, the Baby Deltic less than a quarter of this. Although they suffered problems with the cylinder liners that weren't dissimilar to those of the Class 55 Deltics, most of the Class 23's early problems were a variety of failures with the engine ancillaries. The auxiliary gearbox used to drive the compressor and cooling fans was a particular problem, suffering from vibration in its geartrain and a resonant whirling in the long drive shaft to it at particular rpm. Many engines seized because this shaft driving the auxiliaries snapped and then whipped round, rupturing coolant hoses and causing overheating.
By October 1960 the emphasis of failures had shifted from the ancillaries to the engine itself. Locomotive mileages had only reached 40-60,000 miles each, including stoppages, whilst in this 18 months there had been 44 engine changes across only 10 locomotives. Despite a generous availability of spare engines, four of the ten locomotives were out of service at the time. Four main engine problems had been identified:
- Fractured cylinder liners from the injector hole, caused by assembly stresses
- Fractured cylinder liners from the injector hole, caused by electrolytic corrosion.
- Turbocharger bearing failures, caused by exhaust gases leaking through the labyrinth seals.
- Seized pistons, due to poor cooling caused by chemical erosion from incorrect lubricants.
In July 1961 BR suggested replacing the Napier engine with an English Electric 8SVT V8. This would however have added eight tons in extra weight, and so was rejected. EE also pointed out that the locomotives were now highly reliable in general, except when a major failure required the considerable downtime for an engine change.
By around 1963 all the locomotives had gradually been moved to Stratford
Stratford, London
Stratford is a place in the London Borough of Newham, England. It is located east northeast of Charing Cross and is one of the major centres identified in the London Plan. It was historically an agrarian settlement in the ancient parish of West Ham, which transformed into an industrial suburb...
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.
Modification
It was decided by BR and EE to carry out a programme 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 similar to that of the British Rail Class 55British Rail Class 55
The British Rail Class 55 is a class of diesel locomotive built in 1961 and 1962 by English Electric. They were designed for the high-speed express passenger services on the East Coast Main Line between and Edinburgh. They gained the name "Deltic" from the prototype locomotive, DP1 Deltic, which...
s so they looked every bit a 'Baby Deltic'. The locomotives gradually returned to traffic and became very reliable in traffic except for continuing coolant system problems.
Withdrawal
By the late 1960s BR had drawn up a "National Traction Plan", whose aim was to rationalise the number and types of diesel locomotives in traffic (and thus reduce operating costs). The 'Baby Deltics' were an obvious target, being only a ten-strong class, and still beset with operational problems. The locos were 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. These were D5900/3/4/8; D5908 also 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 CentreRailway Technical Centre
The Railway Technical Centre in London Road, Derby, UK, was built by the British Railways Board in the early 1960s to be its technical headquarters....
in 1969. It worked test trains to and from the RTC until 1975, when it was replaced by a Class 24
British Rail Class 24
The British Rail Class 24 diesel locomotives, also known as the Sulzer Type 2, were built from 1958 to 1961. One hundred and fifty-one of these locomotives were built at Derby, Crewe and Darlington, the first twenty of them as part of the British Rail 1955 Modernisation Plan. This class was used as...
. The loco was cut up in 1977, still carrying two-tone green livery with a grey roof and small yellow warning panel.
Preservation
Probably the only part of a Baby Deltic to survive (apart from works plates) is the T9-29 engine and generator from the last one to be cut up. It is at the Deltic Preservation SocietyDeltic Preservation Society
The Deltic Preservation Society is a railway preservation group based in the United Kingdom dedicated to the preservation and restoration of the remaining Class 55 "Deltic" diesel locomotives operated by British Rail from the 1960s to the 1980s.-Formation:...
MPD at Barrow Hill (although not on display), and has now been restored to operational condition.
According to the DPS website Class 37
British Rail Class 37
The British Rail Class 37 is a diesel-electric locomotive. Also known as the English Electric Type 3, the Class was ordered as part of the British Rail modernisation plan....
, 37372 has been re-engined with this T9 engine. It has yet to emerge as a working locomotive.
A photograph of the engine being started has been published in Rail Express magazine, and videos of the event are available online.
A book about the restoration of the sole-remaining 'Baby' Deltic engine has been published by The Baby Deltic Project and is available through their website.
On 5 September 2010, the Baby Deltic Project announced its plans to recreate a replica of the class. This will be achieved by way of rebuilding 37372's body and mounting it on Class 20
British Rail Class 20
The British Rail Class 20, otherwise known as an English Electric Type 1, is a class of diesel-electric locomotive. In total, 228 locomotives in the class were built by English Electric between 1957 and 1968, the large number being in part because of the failure of other early designs in the same...
bogies.
Models
The Class 23 "Baby Deltic" has been made as a kit from Silver Fox models. Between 1960 and 1965 the Class 23 was available in 000 (approximately N-gauge) gauge as part of the Lone Star "Treble-O-Lectric" range of diecast models in both powered and unpowered versions. During 2011, Heljan introduced a model of the rebuilt class 23 in OO scale.Online sources
- Recognition and equipment information :Class 23 Brief class history and images therailwaycentre.com