That's Libre TrainSim!

Content:
The train simulator has two trains, one suburban track and a metro track.

Free - For everyone:
Libre TrainSim is created by volunteers, who have fun at programming and like trains. The project is hosted on GitHub.

Play on Linux/Windows/Mac/Android:
It doesn't matter, wich OS you are running. For Libre TrainSim that's equal..
The Android version has fewer features and lower graphics.

Easy Start:
With small tutorials you know all the important things how to drive a train, and what you need to pay attention for. If you don't want to drive at all, there's even an autopilot.