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DMU Engines


Introduction

Almost all DMU power cars had two underfloor mounted engines, each driving the inner axle on the closest bogie.

Underfloor DMU engine

There were five main types used:

There were a variety of other types used in small numbers:

  • AEC 219 (125hp) - the ACV railcars
  • Buessing (150hp) - the five Waggon und Maschinenbau railbuses
  • Gardner (112hp) - the two Bristol CV/Eastern CW railbuses
  • Leyland 600 (125hp) - the West Riding Derby Lightweights
  • Meadows (105hp) - the six Wickham railbuses: five passenger and the Elliot Track Recorder

The Blue Pullman had a NBL/MAN 1000hp diesel electric arrangement more akin to a diesel locomotive but also had Rolls Royce C8 engines for auxiliary power.

The railbuses only had one engine per vehicle, as did two types of DMUs — the Cravens Class 112 and 113s.

Many engines were sold and badged under the "British United Traction" (BUT) brand, a collaboration between AEC and Leyland.

On each power car engines were labelled as "Engine No.1" and "Engine No.2". Number one was on the number one side of the vehicle — the side on which the driver sat — and drove the front bogie. Number two was on the opposite side and drove the rear bogie.

The Cravens Rolls-Royce sets (Classes 112/3) had just one engine per power car, and the railbuses had just one engine. In the 1980s one Class 104 and a batch of Class 111s had one engine removed from each power car.

In the 1970s were was a re-enginning programme to reduce the number of AEC engines, they were replaced by Leyland 680s - both were 150hp engines with the same mountings.