It should be possible to change the enginespec from that for a carriage/passenger car to that for a locomotive.
My 'representations' of the Classic Paris Metro rolling stock each use the same style of body but different enginespecs depending on whether a motor- or non-motor car.
These were made for TRS2004 using generic, built-in enginespecs - on the DLS look for 'Sprague ...' if it would help.
Ray
You will also need to alter engine 0 to engine 1. A better example is my '4compt pp B3rd brown' on the DLS which is made from my similar non-motorised coach.
