Hello Lisa,
may I suggest that you couple the short and long cassette together, so that the short one
is next to main track.
So when you push the train back the wagons will come to a rest on the long cassette and the
engine on the short one, next you uncouple the two cassettes and move the long one towards the
track and the short one right from the long one, and couple them both together, now you couple
the engine on the train and push the wagons back to the platform.
Markus