I've really enjoyed playing this, the combination of building the railroad and acting as controller of the trains.
It's trickier than I first thought and if you get your road design wrong it causes all sorts of problems later on, but that's the fun of it.
I would like to have a way to see the routes you can build on before starting to add rails, and the ability to quickly cancel a build by pressing ESC or some other key - at the moment you have to retrace the route you are laying with the mouse in order to cancel sections of track.
The "P" key pauses the game but you cannot press it again to un-pause it, which is a bit annoying as you have to click the button in the top left of the screen with the mouse.
It would also be nice to be able to pull up tracks you have already laid in order to improve your railroad, but maybe that's the design of the game to make it harder.
Overall I'm happy with the game, I can see many hours of happy play.