Do you use Digitrax DCC? If yes, there's s/w you can get to program your decoders and also control the turnouts on your layout.
You can also use it for track planning with XTrkCAD or Atlas RTS (both free).
You can run s/w for waybills and car cards, and generate shipments between your industries.
You can always use it like a traditional computer too - a db or spreadsheet for your locos and rolling stock. Store pictures, video and railroad music
That should keep you busy for a while.
Andrew