I know that these are small things, but I have some ideas to make these functions a bit better:
-Terminal stations to end track and handle more trains
-Dedicated freight stations that aren't a part of trade ports
-The ability for railroads to serve certain industries directly
-Possibly a different, more Americanized version of the default trains
-Subways and subway stations
-Dedicated wharfs/docks and waterfront warehouses
Possibly also transportation HQs, such as a Railroad HQ and a Shipping HQ.
What do you guys think?