Utility man... Another name is the Conductor or head end Brakeman, 
Most Railroad already have road repair trucks manned by the car department that can handle serious repairs, Changing wheels, broken air pipes etc providing they can drive to location where the car has been set off. CN even had road repair railway cars that the car dept could live in and the cars also would have all their equipment, wheels, trucks, whatever repairs needed to get the car on the move at least to the next large terminal.
It would be impossible for a utility vehicle to reach some of these locations, (no roads) Now you also run into the qualification of the utility man. Is he a trained trainman(conductor/brakeman) car dept employee or a little of both,
Has to be a better way. You could be sitting there for hours and hours waiting for a so called expert utility man, Dumb idea.
