This "sim" is fairly nice looking graphically but otherwise is not very realistic and is more aimed at the gaming community than the simulator community as that is where the money is.
The DLC is very expensive and if you want more than a couple of basic routes and loco's be prepared to pay!
The forums on steam have been closed by the producers of this game as many people pointed out the obvious flaws and lack of any real update to fix them. If you want a realistic train simulator then I recommend looking elsewhere. Even Microsoft train simulator is better and it came out in 2001!