Hello again,
I updated to Mavericks as well and it has been flawless since then (touch wood). It has not crashed (touch wood) and there aren’t too many bugs in my opinion. I guess it just doesn’t work on Lion. I suppose the game itself is a bit nerdy and technical but you get used to it, I just like watching the trains :). One thing I do wish they would do is create a screen mode where none of the tools or tabs on the edges are visible, like Cities in Motion 2 as I am sure this would make the game run more smoothly, especially at lower angles which my computer cannot handle.
Thanks again for your help!