Trains can be used to transport resources quickly over long distances as well as crossing water or inaccessible areas.
Trains can be freely constructed at the ‣. Once built you can assign a train a transport route.
You can assign a train to stop at train stations(‣). You can assign as many stations as you like to a route but make sure that each subsequent station can be reached. Also be aware that if a train meets another train coming in the opposite direction then both will stop and you'll need to destroy one of the trains to allow the other to continue on its route so make sure your trains do not run on conflicting routes.
By default, at every train stop the station stackbots will load all types of resources onto the train. You can change this by adding rules to a train stop. You can also set import and export rules for a whole station. For full details check out the Transport Rules section.