APPENDIX "A"

DIESEL MULTIPLE UNITS

STANDARDISATION OF UNDERFLOOR POWER EQUIPMENTS

With reference to Minute 470 of the Modernisation Committee, the following reports the position and makes recommendations concerning the power equipments to be adopted for all future multiple unit diesel trains having underfloor engines:-

1.  Present Position

The majority of diesel multiple units so far produced both in railway shops and by manufacturers have been fitted with two diesel engines per power car of 150/180 H.P. each. These have been used in the following combinations:-

2.  Experimental Units

Trials with higher powered underfloor engines have been successfully carried out, introducing further possible choice in motive power as under:-

3.  General Considerations

The call for greater engine power arose first with 63' 6" vehicles where heavier gradients and/or operating conditions than hitherto had to be met. To meet these conditions, power provision of 460/476 H.P. per 2-car set (motor + trailer) is now available with the larger 230 H.P. and 238 H.P. engines developed by B.U.T. and Rolls-Royce respectively.

Loading guage considerations limit the length of vehicle which can run on many secondary and branch lines to 57 ft. and it is not reasonably practicable, due to restricted space, to fit two of the larger engines to such vehcicles. There is accordingly no means, while retaining the two engine per motor car arrangement, of obtaining increased power between 300 H.P. per 2-car set (M + T) and 600 H.P. per 2-car set (M + M).  Where power requirements for given routes fall intermediately with 57 ft. vehicles, the appropriate alternative is to provide one engine of 230/238 H.P. per vehicle, which for a 2-car set gives a total of 460/476 H.P.

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