|Edward Thompson (engineer)|
|Born||25 June 1881
Pembroke College, Cambridge
|Engineering discipline||Mechanical engineering|
Edward Thompson (1881–1954) was Chief Mechanical Engineer of the London and North Eastern Railway between 1941 and 1946. Edward Thompson was born at Marlborough, Wiltshire on 25 June 1881. He was the son of an assistant master at Marlborough College. He was educated at Marlborough before taking the Mechanical Science Tripos at Pembroke College, Cambridge. Thompson's academic background contrasts with that of his predecessor Nigel Gresley, who had also attended Marlborough, but then gained practical experience as a pupil at Horwich Works.
After graduation Thompson worked in both industry and the railways for a while. By 1910 he was assistant divisional locomotive superintendent on the North Eastern Railway (NER), in which capacity he gave evidence at the inquiry into the fatal accident between two goods trains at Darlington on 15 November 1910. In 1912 he was appointed Carriage and Wagon Superintendent for the Great Northern Railway (GNR). He remained at this post for 18 years until he became Workshop Manager at Stratford Works in 1930. This was his final post before becoming Chief Mechanical Engineer (CME) of the London and North Eastern Railway (LNER) in 1941 after the death of Nigel Gresley. Edward Thompson retired from the post of CME in 1946. Gresley and Thompson disagreed on a number of matters. The biggest dispute between them was on the Gresley conjugated valve gear for 3-cylinder engines. This valve gear arrangement worked well during peacetime but experienced problems due to poor maintenance during the Second World War, giving Thompson some justification for his criticism of the design.
When Thompson was appointed CME of the LNER he started a much needed standardisation programme. This programme demonstrated Thompson's dislike for Gresley’s engineering practices. Many notable Gresley designs were rebuilt under this practice including the P2 Mikado, V2 Prairie and A1 Pacific locomotives. The A1 chosen for rebuilding was Great Northern, this being the original Gresley prototype for the class.
While Thompson criticised many of Gresley’s practices, equivalent comment can be made about many of Thompson’s designs. His Pacific rebuilds were not the best designs. They all retained three cylinders, but with divided drive and 3 sets of independent Walschaerts valve gear. Thompson attached great importance to having the connecting rods equal in length, which was in fact unnecessary. As a result the outside cylinders were placed behind the front bogie with the inside cylinder well forward. This gave the engine an unnecessarily long wheelbase, created long exhaust channels and encouraged flexing and fracture of the locomotive frames. All of his Pacifics were particularly prone to wheel slip. The problems with Thompson's Pacifics were such that they were withdrawn and scrapped before many of their older counterparts. Thompson omitted the "banjo dome" that had featured on the Gresley Pacifics since 1928. However, Thompson's successor, Arthur Peppercorn, revived the feature on the remaining batches of LNER Pacifics.
Thompson’s class L1 Adriatic suburban tank locomotives were another unsuccessful design. They were powerful machines that should have been well-suited to their duties but their 5 ft 2 inch wheels were too small for the fast outer suburban services and they quickly knocked themselves apart. The axle boxes suffered, water tanks split, oil pipes broke off, and crossheads wore rapidly.
On the other hand Thompson built one of the most successful LNER designs, the class B1 4-6-0, which was a simple two-cylinder design mixed traffic engine. The B1 was based loosely on Gresley's class B17. The prototype for the B1 was a B17/1 modified with a higher pressure boiler and with its centre cylinder removed. More than 400 B1's were built between 1946 and 1952, British Railways having continued B1 production after nationalisation. The boiler used in the class formed the basis for the rebuilding of many pre-grouping classes, including the class O4 2-8-0 freight locos. The Thompson B1 equalled the LMS Black Five locomotives during inter-regional exchange trials in the early years of British Railways. The B1 was also cheaper to build than the Black Five. The B1 had poor and very inconsistent ride quality, unlike the relatively smooth riding qualities of Gresley designs. Poor riding remains a characteristic of B1's that have been preserved.
Thompson improved passenger safety by introducing steel-bodied coaches to the LNER. Hitherto the LNER had Gresley-designed coaches, the most famous of which had Teak bodies but by 1940's standards these were considered insufficiently safe in a collision. Therefore during the Second World War Thompson designed new all-steel coaches that became a forerunner of British Railways Mark 1 design.
Shortly before Thompson's retirement the LNER was short of express passenger locomotives so Thompson initiated plans for a new Pacific design, which he intended to be based on the rebuilt Great Northern. However the LNER design office, having received reports of Great Northern's performance in service, continually delayed designing the locomotive until Thompson had retired. Even then Thompson laid down a strict set of guidelines for the new loco's. The new class (LNER Class A1) was finally designed under Thompson's successor Arthur Peppercorn, who disregarded almost all of Thompson's guidelines.
Thompson retired from the LNER in 1946 and died in 1954.
|Chief Mechanical Engineer of the
London and North Eastern Railway
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