The tour bus arrived late and we missed the scheduled train. I want them to pay for the new train ticket I had to buy.

It is not uncommon for tour buses to get stuck in traffic, especially as they travel around to popular tourist spots. A tour bus is not connected to any trains, and the pamphlets and daily schedule always state that arrival times are only estimates. For that reason, it is going to be difficult to get the bus company to pay for your train ticket.