Side view finished model
Parts of the Bachmann mechanism are just visible between the cross members. It just so happened that everything worked out to allow the body to sit at the correct height. The power unit is kept in place with some Bluetack or Elmers sticky putty stuff. The engine on the original railtrucks was a JAP two-cycle aircooled engine. There was chain drive to the gearbox and from there to the axles with two forward and two reverse speeds. There were front and rear sandboxes with the control levers sticking up at the back.