My favourite railway is and was always Port Ogden and Northern by Jim "Sniper" Ward. Now of course I tried to run it in OpenRails and ran into several problems. First, the runactivity.exe lists a whole bunch of errors which can only be caught in a screenshot. Mainly it was about some dynamic track portions not found. Then a system exception "the wagon is on a piece of track not found" or so. It should be fairly easy to reproduce the problem.
After some time the simulation screen came up, and I could finally start driving. The consist I had chosen has two GP-38 back to back. These were separated by a rather big gap into which a third loco could easily have fit, but I cannot see anything there. Anyway, the whole consist started moving in the end.
Next: at many places the trees were growing right out of the tracks.
Also, the cursor would not be visible on the screen; only when I moved it off the game window it would be visible. Which of course prevented me from throwing switches - G and Ctrl-G would not work either.
Finally: would it be possible to capture the output of runactivity.exe in a text file which one could then add to any error report that might come up. Might give you a lot of additional info you need to improve the program (so far it is really great, considering that you are not so long on the air).