This is an early version of my attempt at simulating a model train set.

Use the Throttle slider or Up and Down arrow keys to control train speed.   Trains normally go right at 3-ways, straight at 4-ways.   Use Left and Right arrow keys to make turns.   Click the Color box to cycle through train colors.  

Add cars to the train by clicking the Length window (shift click to remove).   Add trains (3 max) by clicking Control window background (shift click to remove).  

Press Ctrl (on keyboard) to cycle through which train is under keyboard control.  

Click Overview if you want to see some of the internal workings of the program.