Train Sim World 2

After completing a few full runs along the line to get in my 100km achievement for the loco, the easiest way by far is to go into Explore > Timetable > Continue .... then pick any of the Runaround services at Arosa or Chur. They take about 3-4 minutes each once you get used to them and the count for Services / Gold Medals.

A few notes.
In the description it mentions manual points .. I never had to change any.
The distances are so short you can full throttle most of it.
Make good use of the Camera Mode .. for reversing / coupling, quicker than getting out.
Be careful with the Red lights. I held to contact Signaller before most moves, just to be safe