No different to earlier versions I'm afraid. Unless you run it in windowed mode then you will have to use Fraps or similar. Average FPS is recorded in jetlog.txt by the way.
He's talking about a Frames Per Second display so you can see what effect assorted tweaks have on framerates. Every simulator and first person video game since 1985 you hit SHIFT Z and get an FPS counter in one of the corners, Trainz either never heard of that technology or they didn't want us seeing the FPS. :hehe: But either Fraps or running in a window will do it.