Thats a time consuming thing. Theres no wayside on the station platforms and trains running layovers of just a few hours or less it does not make sense to do. Plus there is often not any personell around to connect it. It isnt just like a electric car where you can plug it in and go. You need to reconfigure the locotmotive, shut it down, blue flag the track and connect the ground power. Reverse for when its undone.
No good deed goes unpunished.