There are so many possibilities for this game. Passengers would have a need to travel to smaller towns (like a lumber or mining town) for work.
Cities would always have a demand for some product so rail lines would always be busy. I have no idea how difficult these changes would be to make but they would make the game so fantastic. Slow down time a little bit as well, change the 20 minute rule. You could even have a military base pop up with a job to move military cargo to port for deployment overseas. The name of the game is Train Fever not transport by wagon and truck fever so please provide us with the tools to use trains more effectively.