I have to say that trailing back to my earliest version of Trainz, 2006, I have had exactly one crash, a few months ago, and was able to reconstruct everything I had built to that point. Seems to me that Trainz is a fairly robust program. I wanted to add that this is not a criticism of you, just an observation. I wonder if your experience, repeated by others from time to time, has more to do with other programs you have installed on your machine than it does with the program itself.
Bernie