MaSzyna is a free, polish train simulator. The program allows you to put yourself in the role of a train driver and conduct a large number of locomotives/trains, for example EU07, SM42, EP09 or electric multiple unit EN57. MaSzyna executable source code is licensed under open-source license, and comes with huge pack of free assets, on custom license.
Currently latest release is MaSzyna 17.07, for which automatic NSIS installer can be downloaded here. Please note that documentation, which you will need to start any locomotive isn't up to date with control changes in latest release. Main difference is that previous SHIFT+[key] to enable, and [key] to disable device was replaced by just [key] toggling between possible states. Another critical change is brake control, which is now: locomotive brake: Num 7 - decerase braking, Num 4 - releaser, Num 1 - increase braking, and train brake: Num 9 - decrease braking, Num 6 - 'drive' position, Num 3 - increase braking. Also almost all controllable elements can be activated by mouse; mouse mode is activated by ALT key.
Though latest release only contains executables for Windows, simulator should run flawlessly using Wine. Native Linux support is in final development stage and instructions should be available shortly.
In case of any problems with simulator, don't hestitate to ask on our forums.
Movie - @ AnteqKolejowy
Music - @ mk1991