In spite of some people having success, I have elected to continue the process of breaking the scenario into two parts, one out and the second back. While some people have found "work-arounds", I would like non-technical players to concentrate on the route and the challenge of dealing with a heavy, slow accelerating, slow braking train. The second part has allowed me to add a couple of AI train meet challenges on the trip back, that I think you will find interesting...
A Spoiler below
The added challenge is due to the need to plan ahead to allow stopping prior to a red signal with a locked switch set against the player. A player who blindly drives the speed limit assuming that the signal will clear or they will be able to stop from full speed when they see a stop ( red signal, ) will be surprised that it just doesn't work that way.