It's buggy. The game doesn't have option to exit, neither it asks you to save your progress, so next time you relaunch it after forced shutdown, Voila, you've lost a lot of progress, time and money you spent on upgrading objects. And there are just too many train names. Would be easier to classify trains based on colors. Why does upgrading gets exponentially expensive with progress? They just want you to spend your money but there's no point in doing that if your progress isn't saved.