A brief overview - 1962 to 2001
by Dennis Hoy
The concept of a dual-powered locomotive for the S.R. was first raised in the 1930's. The idea was considered for the early S.R. locomotives 20001-20003 (Class 70) and the later B.R. type E5000-E5023 (Class 71) but rejected in favour of the booster system. The booster unit, in the form of a flywheel-driven generator enabled the traction motors to be powered over short gaps in the conductor rail such as points and level crossings and prevented the locomotive from becoming stranded on a 'dead' section of track. The S.R. operating department also insisted that any design should have comparable power on both diesel and electric, requiring a relatively large diesel engine.
The idea was revived again after World War 2, when the operating department rejected designs for a centre-cab locomotive and a motorised luggage van. It was in 1956 that design work commenced at Brighton Works for the initial electro-diesels. This preceded the order for the Cromptons (class 33) but authority to build six prototypes (class 73/0) was not given until 1959. Some features of the Cromptons were incorporated in the design of the electro-diesels such as the electric output of 1600hp closely matching the 1550hp output of the Crompton. They were also fitted with the standard 'blue star' coupling code allowing them to work in multiple. The slab-sided appearance was to increase the route availability to the maximum by allowing access to the narrower Hastings gauge. The final batch of Cromptons was also built to this gauge.
The series of six prototypes were built in the carriage works at Eastleigh by the Southern Region, and were designated type JA. The first, E6001 entered traffic on the 1st February 1962 and the last, E6006 on 15th November 1962. The six were delivered in B.R. Southern Region carriage green, with light grey window surrounds, dark grey roof, red bufferbeams and black bogies. They carried the carriage-style lion and wheel BR emblem. This was the colour scheme that suited them best, but was changed to blue for the second batch. E6001 was delivered with small yellow warning panels on both cab ends but this was soon replaced by a light grey band extending round the locomotive at sole bar level. Sanding gear was later fitted to this locomotive. Oval carriage buffers were fitted to E6001-E6003 when delivered new, but these were later changed for those of the round style. They weighed 73 ton 16 cwt empty or 75 ton 2 cwt in full working order with a maximum speed of 80 mph. The continuous tractive effort on electric power was 9600lb at 55.5 mph, power being 1420hp at the rail with a traction current of 1700Amp. Maximum tractive effort was 42000lb, maximum power was 2420hp at 37 mph. On diesel, the engine was rated at 600 hp and generator at 850Amp resulting in 430 hp at the rail, and resulting in a maximum tractive effort of 36000lb.
Stewarts Lane was chosen as the maintenance site as it was appropriate that these new locomotives should share the new purpose-built electric depot with the older electric designs. The training school here also produced the drivers' manuals, explaining the principle of dual power and how the EDs could work in multiple with each other and any other `blue star` locomotives. They could also work in multiple with 1951 and 1957 emus and luggage vans.
Driver training on the dual power principle was carried out between New Cross Gate and the South Coast. After this, the locomotives worked duties from several depots on the S.R. From Hither Green, they shared work with the Cromptons, including van trains to the Kent Coast and transfer freights to Feltham marshalling yards. They were also used on diesel power in the sidings and yards at Hither Green, Gillingham and Faversham and since conductor rail was absent in these places, allowed direct comparison with the Class 71s using the overhead current collection method.
A test run in 1962 involved E6003 + E6004 (then brand new), with nine coaches and a dynamometer car from Stewarts Lane to Dover. With a guaranteed clear road, 100 mph was obtained between Ashford and Tonbridge. In 1964, a similar test using E6001 + E6006 and Kent Coast emu stock achieved 88 mph. During these tests, stresses in the track and coaches were measured first on hauling, then on propelling the train. The conclusion reached was that the use of screw couplings between coaches was inadvisable, and buckeye couplings should be used for push-pull operation. These early results were to be useful during the development of the Bournemouth electrification scheme resulting in the 8-TC + 4-REP push-pull combination from 1967. Further push-pull trials were carried out during June 1965 using E6006 with new 4-CIG Brighton express units on the Waterloo-Fratton-Alton circuit.
The 6 prototypes must have created an impression, for within 18 months, a further 30 locomotives were ordered by the BTC, and later increased by 13 due to the Bournemouth electrification scheme. The order was placed in June 1963, and built under contract by the English Electric Co. at the Vulcan Foundry. The new batch were classified JB by the S.R. and were numbered E6007-E6049 (now class 73/1 and 73/2). These were delivered between October 1965 and January 1967 and all were driven south under their own diesel power. The first of the batch, E6007-E6013, were painted in the 'electric blue' livery and had the grey band at sole bar level. The rest were delivered in the new corporate image 'Rail Blue' and were the first to use this semi-matt colour scheme with the associated symbol on the bodyside.
The two types appear very similar externally, but the JBs are fitted with the Mk. 6 motor bogie, as used in the 1967 Bournemouth emus. The more sharp-eyed will notice that the JAs also have an extra jumper cable fitted under the driver's window, an extra window in the bodyside, and the thicker buffer beam at No. 2 end to balance the weight of the engine fitted towards the No. 1 end. With the arrival of the JBs, driver training commenced in earnest between Eastleigh and Basingstoke, Stewarts Lane and Wimbledon and at Hither Green when locomotives were available.
The JBs were quickly employed on duties from Feltham including carriage shunting at Clapham Junction yard and pick-up freights on the Portsmouth line. Feltham lost its last booked stem working from 24th July 1965 when the Waterloo-Reading and return parcels turn was booked for ED haulage. Maintenance was mainly carried out at Stewarts Lane where the fitters were familiar with electric traction. The staff were given basic diesel training at Hither Green and this combination seemed to work well in practice. Very little work was carried out at Hither Green except for refuelling and brake servicing, due to the lack of electrically trained fitters.
During the first few years of service, the JAs were tried on passenger trains including the Golden Arrow and Night Ferry boat trains. 73002 and 73004 carried the small brackets for the headboards until their demise. The JBs were used almost exclusively on freight traffic on all three divisions of the Southern Region, and some cross-London transfer freights.
At the end of 1966, JBs E6007-E6028 were reallocated to Eastleigh for working engineers' trains on the Bournemouth electrification scheme. This was the one and only time that EDs have ever been allocated away from Stewarts Lane. At the same time, D1921-D1926 (now class 47) were also allocated to Eastleigh for working the Bournemouth Belle. The power was switched on from the 10th July 1967 and steam finally disappeared from the Southern Region. The EDs had returned to Stewarts Lane by June 1968 and the borrowed class 47s returned to the Western Region with the delivery of the class 74 ED conversions from class 71. The class 73 EDs continued to work with TC units on main line duties to Weymouth and everywhere on freight and engineering trains.
The numerical classification of locomotives was introduced during 1968. The JAs became class 72 and the JBs became class 73. This was altered during the late 1969 when class 72 became class 73/1 and class 73 became 73/2. This was to change yet again in 1974 when the TOPS system was introduced.
From 1970, the EDs worked much of the freight and parcel traffic throughout the Southern Region. They were also very popular for engineering trains as they could be used when the power had been turned off. They were also rostered for Royal trains on Derby Day and VIP special trains. Withdrawal of the S.R. class 70s meant that the Newhaven boat trains had Class 73 haulage before being replaced by emus.
On 12th October 1972, E6001 was involved in a collision between a coal train and a suburban emu at Wimbledon. One cab of the ED was damaged by the coal hopper wagons that it was hauling. The locomotive was repaired and received a cab from withdrawn E6027 which had been withdrawn earlier that year as a result of accident damage.
The new TOPS renumbering scheme was introduced in 1974 and the class 73/1 became 73/0 and 73/2 became 73/1. The JAs became 73.001 to 73.006 and the JBs were numbered 73.101 to 73.142. All were numbered in sequence with a gap due to the unfortunate E6027. The livery was modified to conform with the new corporate identity by painting the roof blue, bufferbeam black and applying overall yellow warning panels to the cab ends.
A change of livery was introduced during 1984 when some class 73s emerged from works overhaul painted in the new express livery of blue with wrap-around-yellow ends and black window surrounds. They also carried the large BR number and logo.
73.005 ventured as far as Derby on the Midland main line to collect unit 5850 from the technical centre on 30th June 1986. It failed at Wellingborough on the return journey and 73.004 was sent as the rescue locomotive and the pair returned together, making an unusual sight on the Midland main line.
Official namings included 73004 'The Bluebell Railway' on 19th September 1987 and 73.005 'Mid-Hants Watercress Line' on 10th September 1988.
From the May 1993 timetable, the JAs became surplus to requirements and were withdrawn from service. 73.003 had been repainted at Selhurst Level 5 depot in original green livery and named 'Sir Herbert Walker' to mark the closure of the works at the end of March 1993, and was retained by Network South East for use on charter trains.
The remaining JAs were unexpectedly claimed by Regional Railways for further use on the Merseyrail system for sandite duties. 73.001 and 73.006 were repainted into Merseyrail yellow livery the locomotives proved popular with the crews. 73.005 was repainted into blue and retained as a depot shunter at Birkenhead North. A change of policy resulted in the storage of the Mersyside JAs which have recently been offered for sale as surplus to requirements.
The sole remaining locomotive E6003 saw use on the Mid-Hants railway and was rumoured to go to the NRM upon withdrawal. This proved not to be the case and after eighteen months of secure storage, was sold to EDLG after being offered for sale by EW & SR by competitive tender during 1996. The locomotive was moved to the Lavender Line in early 1997 and commenced regular working on the line from Easter 1997. The locomotive has worked most of the service trains from that date until recently when it was withdrawn for essential maintenance work. It has been offered on loan to the Great Central Railway at Loughborough for an indefinite period following completion of this work.
Practical rather than glamorous in appearance, the EDs have been remarkably free from serious problems and are well liked by train crews. For over 30 years and until closure by EW & S R, Stewarts Lane depot was responsible for most of the fleet, surely a record for any class of locomotive.
The concept of a dual-powered locomotive for the S.R. was first raised in the 1930's. The idea was considered for the early S.R. locomotives 20001-20003 (Class 70) and the later B.R. type E5000-E5023 (Class 71) but rejected in favour of the booster system. The booster unit, in the form of a flywheel-driven generator enabled the traction motors to be powered over short gaps in the conductor rail such as points and level crossings and prevented the locomotive from becoming stranded on a 'dead' section of track. The S.R. operating department also insisted that any design should have comparable power on both diesel and electric, requiring a relatively large diesel engine.
The idea was revived again after World War 2, when the operating department rejected designs for a centre-cab locomotive and a motorised luggage van. It was in 1956 that design work commenced at Brighton Works for the initial electro-diesels. This preceded the order for the Cromptons (class 33) but authority to build six prototypes (class 73/0) was not given until 1959. Some features of the Cromptons were incorporated in the design of the electro-diesels such as the electric output of 1600hp closely matching the 1550hp output of the Crompton. They were also fitted with the standard 'blue star' coupling code allowing them to work in multiple. The slab-sided appearance was to increase the route availability to the maximum by allowing access to the narrower Hastings gauge. The final batch of Cromptons was also built to this gauge.
The series of six prototypes were built in the carriage works at Eastleigh by the Southern Region, and were designated type JA. The first, E6001 entered traffic on the 1st February 1962 and the last, E6006 on 15th November 1962. The six were delivered in B.R. Southern Region carriage green, with light grey window surrounds, dark grey roof, red bufferbeams and black bogies. They carried the carriage-style lion and wheel BR emblem. This was the colour scheme that suited them best, but was changed to blue for the second batch. E6001 was delivered with small yellow warning panels on both cab ends but this was soon replaced by a light grey band extending round the locomotive at sole bar level. Sanding gear was later fitted to this locomotive. Oval carriage buffers were fitted to E6001-E6003 when delivered new, but these were later changed for those of the round style. They weighed 73 ton 16 cwt empty or 75 ton 2 cwt in full working order with a maximum speed of 80 mph. The continuous tractive effort on electric power was 9600lb at 55.5 mph, power being 1420hp at the rail with a traction current of 1700Amp. Maximum tractive effort was 42000lb, maximum power was 2420hp at 37 mph. On diesel, the engine was rated at 600 hp and generator at 850Amp resulting in 430 hp at the rail, and resulting in a maximum tractive effort of 36000lb.
Stewarts Lane was chosen as the maintenance site as it was appropriate that these new locomotives should share the new purpose-built electric depot with the older electric designs. The training school here also produced the drivers' manuals, explaining the principle of dual power and how the EDs could work in multiple with each other and any other `blue star` locomotives. They could also work in multiple with 1951 and 1957 emus and luggage vans.
Driver training on the dual power principle was carried out between New Cross Gate and the South Coast. After this, the locomotives worked duties from several depots on the S.R. From Hither Green, they shared work with the Cromptons, including van trains to the Kent Coast and transfer freights to Feltham marshalling yards. They were also used on diesel power in the sidings and yards at Hither Green, Gillingham and Faversham and since conductor rail was absent in these places, allowed direct comparison with the Class 71s using the overhead current collection method.
A test run in 1962 involved E6003 + E6004 (then brand new), with nine coaches and a dynamometer car from Stewarts Lane to Dover. With a guaranteed clear road, 100 mph was obtained between Ashford and Tonbridge. In 1964, a similar test using E6001 + E6006 and Kent Coast emu stock achieved 88 mph. During these tests, stresses in the track and coaches were measured first on hauling, then on propelling the train. The conclusion reached was that the use of screw couplings between coaches was inadvisable, and buckeye couplings should be used for push-pull operation. These early results were to be useful during the development of the Bournemouth electrification scheme resulting in the 8-TC + 4-REP push-pull combination from 1967. Further push-pull trials were carried out during June 1965 using E6006 with new 4-CIG Brighton express units on the Waterloo-Fratton-Alton circuit.
The 6 prototypes must have created an impression, for within 18 months, a further 30 locomotives were ordered by the BTC, and later increased by 13 due to the Bournemouth electrification scheme. The order was placed in June 1963, and built under contract by the English Electric Co. at the Vulcan Foundry. The new batch were classified JB by the S.R. and were numbered E6007-E6049 (now class 73/1 and 73/2). These were delivered between October 1965 and January 1967 and all were driven south under their own diesel power. The first of the batch, E6007-E6013, were painted in the 'electric blue' livery and had the grey band at sole bar level. The rest were delivered in the new corporate image 'Rail Blue' and were the first to use this semi-matt colour scheme with the associated symbol on the bodyside.
The two types appear very similar externally, but the JBs are fitted with the Mk. 6 motor bogie, as used in the 1967 Bournemouth emus. The more sharp-eyed will notice that the JAs also have an extra jumper cable fitted under the driver's window, an extra window in the bodyside, and the thicker buffer beam at No. 2 end to balance the weight of the engine fitted towards the No. 1 end. With the arrival of the JBs, driver training commenced in earnest between Eastleigh and Basingstoke, Stewarts Lane and Wimbledon and at Hither Green when locomotives were available.
The JBs were quickly employed on duties from Feltham including carriage shunting at Clapham Junction yard and pick-up freights on the Portsmouth line. Feltham lost its last booked stem working from 24th July 1965 when the Waterloo-Reading and return parcels turn was booked for ED haulage. Maintenance was mainly carried out at Stewarts Lane where the fitters were familiar with electric traction. The staff were given basic diesel training at Hither Green and this combination seemed to work well in practice. Very little work was carried out at Hither Green except for refuelling and brake servicing, due to the lack of electrically trained fitters.
During the first few years of service, the JAs were tried on passenger trains including the Golden Arrow and Night Ferry boat trains. 73002 and 73004 carried the small brackets for the headboards until their demise. The JBs were used almost exclusively on freight traffic on all three divisions of the Southern Region, and some cross-London transfer freights.
At the end of 1966, JBs E6007-E6028 were reallocated to Eastleigh for working engineers' trains on the Bournemouth electrification scheme. This was the one and only time that EDs have ever been allocated away from Stewarts Lane. At the same time, D1921-D1926 (now class 47) were also allocated to Eastleigh for working the Bournemouth Belle. The power was switched on from the 10th July 1967 and steam finally disappeared from the Southern Region. The EDs had returned to Stewarts Lane by June 1968 and the borrowed class 47s returned to the Western Region with the delivery of the class 74 ED conversions from class 71. The class 73 EDs continued to work with TC units on main line duties to Weymouth and everywhere on freight and engineering trains.
The numerical classification of locomotives was introduced during 1968. The JAs became class 72 and the JBs became class 73. This was altered during the late 1969 when class 72 became class 73/1 and class 73 became 73/2. This was to change yet again in 1974 when the TOPS system was introduced.
From 1970, the EDs worked much of the freight and parcel traffic throughout the Southern Region. They were also very popular for engineering trains as they could be used when the power had been turned off. They were also rostered for Royal trains on Derby Day and VIP special trains. Withdrawal of the S.R. class 70s meant that the Newhaven boat trains had Class 73 haulage before being replaced by emus.
On 12th October 1972, E6001 was involved in a collision between a coal train and a suburban emu at Wimbledon. One cab of the ED was damaged by the coal hopper wagons that it was hauling. The locomotive was repaired and received a cab from withdrawn E6027 which had been withdrawn earlier that year as a result of accident damage.
The new TOPS renumbering scheme was introduced in 1974 and the class 73/1 became 73/0 and 73/2 became 73/1. The JAs became 73.001 to 73.006 and the JBs were numbered 73.101 to 73.142. All were numbered in sequence with a gap due to the unfortunate E6027. The livery was modified to conform with the new corporate identity by painting the roof blue, bufferbeam black and applying overall yellow warning panels to the cab ends.
A change of livery was introduced during 1984 when some class 73s emerged from works overhaul painted in the new express livery of blue with wrap-around-yellow ends and black window surrounds. They also carried the large BR number and logo.
73.005 ventured as far as Derby on the Midland main line to collect unit 5850 from the technical centre on 30th June 1986. It failed at Wellingborough on the return journey and 73.004 was sent as the rescue locomotive and the pair returned together, making an unusual sight on the Midland main line.
Official namings included 73004 'The Bluebell Railway' on 19th September 1987 and 73.005 'Mid-Hants Watercress Line' on 10th September 1988.
From the May 1993 timetable, the JAs became surplus to requirements and were withdrawn from service. 73.003 had been repainted at Selhurst Level 5 depot in original green livery and named 'Sir Herbert Walker' to mark the closure of the works at the end of March 1993, and was retained by Network South East for use on charter trains.
The remaining JAs were unexpectedly claimed by Regional Railways for further use on the Merseyrail system for sandite duties. 73.001 and 73.006 were repainted into Merseyrail yellow livery the locomotives proved popular with the crews. 73.005 was repainted into blue and retained as a depot shunter at Birkenhead North. A change of policy resulted in the storage of the Mersyside JAs which have recently been offered for sale as surplus to requirements.
The sole remaining locomotive E6003 saw use on the Mid-Hants railway and was rumoured to go to the NRM upon withdrawal. This proved not to be the case and after eighteen months of secure storage, was sold to EDLG after being offered for sale by EW & SR by competitive tender during 1996. The locomotive was moved to the Lavender Line in early 1997 and commenced regular working on the line from Easter 1997. The locomotive has worked most of the service trains from that date until recently when it was withdrawn for essential maintenance work. It has been offered on loan to the Great Central Railway at Loughborough for an indefinite period following completion of this work.
Practical rather than glamorous in appearance, the EDs have been remarkably free from serious problems and are well liked by train crews. For over 30 years and until closure by EW & S R, Stewarts Lane depot was responsible for most of the fleet, surely a record for any class of locomotive.