Train Routing, for both Train Travel and Train Accommodation, is set up in the Route Builder Step of the Itinerary Builder. Where a route has not been pre-loaded, you can create a custom route based on the train's itinerary. In some cases, Google Train Routing can be used.
Refer to the article [Route Builder: Train Routes](https://scribehow.com/shared/Train_Routes__tK9osd8ORn-5jp3myrXjmA) for information on setting up train routing.