I think it called a auto coach,it be a great addition if dtg decides to add a 060 shunter or another small engine to use as the power while also pulling or pushing a passenger train.This would be for a UK route since the UK used them.
If the south devon mainline was made and included the avocet line then you could see some autocoache action as I know the route was operated by 14xxs on push pull train to exmouth.