The latest version of Train Simulator 2014, (previously known as Railworks, and before that Rail Simulator), has Google Earth integration. This means you can overlay an aerial photograph when you create a route. This will enable you to exactly place stations and tunnels.

It is not very high-resolution, but the facility makes it much easier to make sure your route follows the real route.

How do you do this?

You have to log into your Google account, and then go to the following URL

http://www.w3schools.com/googleAPI/google_maps_api_key.asp

Follow the instructions here to generate a google maps API, and then copy and paste this to the blank field indicated in the options menu in Train Simulator.

Hint:┬áIn the list of services, find Google Maps API v3, and click on “off” to turn it on.

Hot tip: back in TS 2014, go into the world editor, and type “CTRL-G” to see the Google Earth overlay.