I don't have a Xbox so I have no interest in getting the beta for that but as a beta tester for many of the PC versions of Trainz over the years I do have some advice.
- Beta versions are not for the faint-hearted. Their purpose is to find bugs (and there are always plenty of them in the early beta versions). Unless you are prepared to spend your time on the Xbox beta version testing and exploring to find and report bugs, and not just "playing", then don't bother.
- Don't do any serious Trainz development work in a beta version. It can all be destroyed in an instant by a bug.
- Be prepared to put up with and deal with many, many "Assertion Messages" (part of the testing process).