Very poor FPS. In its favour plenty of addon content, unfortunately you have to pay to get a decent download speed for any of the free addons. Bought on impulse after finding the sublime Euro Truck Simulator, I was hoping for an involving and relaxing sim, I'm not a train nerd but I could probably have got into this if it was not for the shocking FPS, mediocre graphics (in some parts graphics would have been sub-standard fifteen years ago, particularly some of the engine interiors) and the restriction on download speeds for content unless you pay just means that everyone who does pay downloads absolutely everything and further lags up the download server.
Its saving grace is an easy to use track editor, and it is another game with a helful, friendly community.
For now, this one is on the back burner.
You'd probably be better off with the Microsoft Train simulator, and paying for their higher priced DLC and a more polished product.