Could you elaborate please.   The reason I ask is the Hornby Rod Drive I have, utilises a totally different chassis casting. The axle centres are higher in the frame to accommodate the larger 14mm wheels (as opposed to correct 12 mm dia in the chain drive) thus maintaining correct buffer height.  The buffer/drag beams have different shape cutouts to the chain drive chassis as per prototype. I can't confirm the correct wheelbase at the mo as my rod drive is away on its holidays che