Ukrainian locomotive operation simulation with a very high level of prototypical fidelity of Russian, Ukrainian and Belorussian locomotives and trains.
https://zdsimulator.eu Free demo available and only $15 for license key. Lots of DLC routes, scenarios and repaints.
Graphics is about MSTS/Trainz level, but once immersed, really don't matter that much. Sound is OK. Cab sway, superelevation are all there.
Focus is on correct operation of the locomotives and running to schedule, down to every switch, relay and valve of importance, failures do occur and you have to make repairs.
Pro mode has a steep learning curve, and knowledge of Russian language is a must.
I speak, read and understand Russian at high school level but have to resort to a dictionary for all the technical terms. Compact instructions in English are available.
For those of you who have travelled by train in the states of the former USSR, it is all very recognisable.