How to use the in-game routeplanner

You can see the optimal routes from any station in your network to another.

Steps to use

Click on the origin station you to open the station window
Click on the destination station to open the station window.
When you having the two station windows open at the same time, go to the "show dominating trips" screen in the origin station.
Select the other station in that screen, even if there is no pax currently in the station with that destination, marked as "(window)".