Does it hurt for one train to push another?

I am running DC. My Thomas train tends to now stop on a hill with the wheels spinning. The slower train comes along behind it and pushes it up the hill. Once at the top Thomas speeds away. The pusher does not even slow down during this process. Is anything getting hurt doing this? The two are not connected and Thomas is just spinning his wheels till he gets to the top. The train being pushed contains 3 Thomas cars (all about half the size of a standard car.)