How to backup the game files so that I won't lose progress in case of hard disk failure or similar situation? Is Steam backup function enough?
It's certainly not a bad idea to back-up your Railworks directory so you can just copy it back if you ever do have to reinstall rather than waiting for everything to download but your progress should all be recorded by Steam. Speaking from my own experience I got a new laptop a couple of years ago and once I'd installed Steam it took care of everything else. All the DLC I'd bought and Workshop items I'd subscribed to were downloaded and in game all the scenarios I'd completed had a tick or star by them as appropriate. I've just got a new desktop machine and hope everything goes as well.
Steam backup will only backup items bought from steam or the workshop items. Any third party downloads won't form part of that so anything you get from AP, UKTS, JT etc will need to be redownloaded Same goes for content YOU create, so any custom scenarios and so on. Backing up your assets and content folders regularly is probably advisable.
