TrainStation 2 allows you to save game progress by using your Google account. This is critical if you get a new device or wish to play on multiple Android devices.
We'll assume you've already created a Google account.
Start your TrainStation 2 and tap the SETTINGS icon.
In the SETTINGS window tap CONNECT ACCOUNT.
Follow the dialogue to connect to your account. Once connected your game progress is saved on Google. You can then download your game progress into a new device simply by using this CONNECT ACCOUNT procedure.