Edward Thompson (engineer)

Edward Thompson (1881-1954) was Chief Mechanical Engineer of the London and North Eastern Railway between 1941 and 1946.

Biography

Edward Thompson came from an academic background having taken Mechanical Science Tripos at Pembroke College, Cambridge, unlike his predecessor Nigel Gresley who gained practical experience as a pupil at Horwich Works. After graduation Thompson worked in both industry and the railways for a while, when in 1912 he was appointed Carriage and Wagon Superintendent for 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 CME of LNER in 1941 after the untimely death of Nigel Gresley. Edward Thompson retired from the post of CME in 1946.

It is widely known that Gresley and Thompson disagreed on a number of issues. Many have interpreted this bitterness as NER (Thompson) vs. GNR (Gresley). Thompson happened to be the son-in-law of Sir Vincent Raven. The biggest disagreement between the two was on Gresley’s 3-cylinder conjugated valve gear. While this valve gear arrangement worked well during peace-time, it experienced problems due to low maintenance during World War 2. This did give Thompson some justification for the criticism of the design.

Practices

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 Mikados, V2 Express goods and A1 Pacifics. The A1 chosen for rebuilding was none other than "Great Northern", this being the original Gresley prototype for the class. SomeWho|date=July 2008 have stated that this rebuild was sheer vindictiveness on Thompson’s part towards his old chief.

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 of designs. They all retained three cylinders, but with divided drive and 3 sets of independent Walschaerts valve gear. Thompson attached a great deal of importance to having the connecting rods equal in length. This was not necessary, and as a result the outside cylinders were placed behind the front bogie with the inside cylinder well forward and an engine with an unnecessarily long wheelbase. This arrangement created long exhaust channels and encouraged flexing and fracture of the loco frames. All of his Pacifics were particularly prone to wheel slips. Such were the problems with his Pacifics that they preceded many of their older counterparts to the scrapheap. There were other features of the Pacific design that Thompson changed too. The Banjo dome, which had featured on the Gresley Pacifics since 1928 was omitted; this proved not to be a lasting demise however, as Thompson's sucessor, A. H. Peppercorn, re-instated the feature on the remaining batches of LNER Pacifics.

Thompson’s L1 class suburban tanks also left a lot to be desired - they were a mechanical disaster.Fact|date=July 2008 On paper at least, they seemed ideally suited to the task, especially with their high power output, however the 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.Fact|date=May 2008

On the other hand Thompson built one of the most successful LNER designs, the Thompson B1. This was a simple two-cylinder design mixed traffic engine, with a 4-6-0 wheel arrangement. They were based loosely off the Gresley B17 design, indeed the Prototype for the class was a modified B17/1, with a higher pressure boiler and the centre cylinder omitted. Over 400 of these locos were built between 1946 and 1952 four years after Thompson's death / in a total of 8 batches. The boiler used in the class formed the basis for the rebuilding of many pre-grouping classes, including the ex-GCR O4 2-8-0 freight locos. The Thompson B1 compared equally with the LMS Black Five engines during the BR exchange trials. It could be argued that the B1 is a better engine than the Black Five due to its cheaper cost of manufacture.

However, even the B1 was not without faults; LNER crews were used to the relatively smooth riding qualities of the Gresley designs, the B1 didnt follow this trend and had a habit for poor and very incosistent ride quality, it is still possible to experience this to this day on the preserved examples of the class.

One evolution that Thompson should be positively creditied with, is the introduction of steel-bodied coaches to the LNER. Hitherto, the LNER had operated using the Gresley-designed coaches, most famous of which is the "Teak" bodied series, however these were not regarded as safe by the standards of Thompson's day, so the new series of coaches that Thompson designed during the war featured all-steel construction, and were a forerunner of British Rail Mk1 design.

Shortly before Thompsons retirement, there was one final twist in the story, the LNER were short of Express motive power, and Thompson had plans initiated for a new Pacific design, the basis of which would be the rebuilt 'Great Northern' however, the design office, having read reports of the engines' performance in service, continually delayed the designing of the engine until Thompson had retired, even then he laid down a strict set of guidlines for the new batch of engines, almost all of which were ignored when the new engines (designated class A1) were finally designed!

Thompson died in 1954, eight years after his retirement from CME of the LNER.

Locomotives

*Thompson A1/1
*Thompson A2/1
*Thompson A2/2
*Thompson A2/3
*Thompson B1
*Thompson B2
*Thompson K1
*Thompson L1
*Thompson O1

External links

* http://www.lner.info/eng/thompson.shtml
* [http://www.steamindex.com/people/thompson.htm Thompson & Peppercorn ] at www.steamindex.com