Well you might be able to find out what edition of Trainz you have. Do you have it on CD/DVD, or is it a digital copy? what is the name of it? Does it say something like Trainz Simulator 2009, Trainz 12, Trainz Classics, etc...? You could also take a picture of the game menu and we might be able to see what version it is. Oh and to add what JCitron said, The requirements for running Trainz have gone up considerably. I won't go into detail as that is a topic for another day, but I have a Custom Built Gaming PC that can run some fancy games such as BeamNG.Drive, War Thunder, X-Plane Flight Simulator, etc... on high/ultra graphics.
But Trainz is a whole new ball game. It pushes even my PC to the limit at higher graphical levels. My PC can in theory run TRS19 on Medium-High graphics, but I run it on low for the sake of faster load times and a more stable FPS. Don't get me wrong, the graphics are still great in my honest opinion, but I must admit that PC gaming to a certain extent is getting more and more expensive now days just to keep up with the pace.