Seven trains that the PCs might one day need to travel openly on, sneak onto, wreck or rob,
There are a myriad of trains that run on the ley lines all through Vallermoore, delivering passengers and goods to their destinations, but they all have to give way by Law when the Royal War Train comes through.
The PCs are sent with a diplomat to another country to protect him and do his bidding. There may be some espionage, rescuing, downright bullying, etc. Could make a nice medieval, special operations background.