Bulletin No:11

The Bulletin concerned the 'performance and efficiency testing' of the English Electric 1000HP Type 1 bo-bo diesel electric locomotive No: D8000 later to be known as the Class 20's.

The locomotive on which the tests described in this Bulletin were carried out was the first main line diesel locomotive to be completed under the Modernisation Scheme. It was designed by the English Electric Co. Ltd., and built entirely by the English Electric group. The English Electric Company actually manufactured the engine and electrical equipment and The Vulcan Foundry at Newton-le-Willows were responsible for the mechanical construction and locomotive erection.

The Type 1 1000 H. P. locomotives were primarily intended for freight and freight-transfer service, and a carriage heating boiler was not, therefore, installed, although a through steam pipe was fitted. The locomotives had a maximum speed of75 m.p.h. and were thus considered suitable for passenger service.

The tests which formed the subject of this Bulletin were carried out to determine the performance and related fuel consumption of the locomotive over its working range, and at the same time to provide data for calculating train schedules. A comprehensive programme of tests was accordingly arranged and carried out in the London Midland Region during July, August and September 1958.        

The tests were conducted by the Locomotive Testing Section, C.M.&.E.E Dept., L.M.Region, employing the Mobile Test Plant, on behalf of the Locomotive Testing Joint Sub-Committee.

Prior to the road trials, the locomotive was subjected to static load tests at the Derby Locomotive Works Test Plant. It was found that there was a degree of hunting of the torque regulator which gave rise to a fluctuation in current considered to be excessive for road testing purposes. There was also a certain disparity between the various cylinder peak pressures and exhaust temperatures. These matters were given the necessary attention prior to commencement of the road trials, which were then carried out on the route Toton - Leicester - Rugby - Market Harborough Derby - Toton. During each test, the Mobile Test Units were employed to control the road speed in suitable increments, i.e. 5 mile/h at the higher and 2 mile/h at the lower speeds.

Further tests were undertaken between Derby and Chapel-en-le-Frith.

Here are a few pictures of the tests and a summary graph.

Pictures are credited where known

The first diesel completed under the Modernisation Scheme D8000
The BR diagram book entry
On test with the MTU and dynamometer car - passing Derby N Jcn
The test train pictured in the Up platform at Market Harborough - it's changed a bit since 1958

W H King

The results showed a maximum of 600HP at the drawbar

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