Im here to shed some hope to some hopeless and give some doubt to the doubters.
There is a very popular park that actually has the train crossing alot of their backstage area, and running right along side it at times... This park is owned by blackstone. They get around it by placing simple railroad crossings, even back stage. and since backstage service roads are generally a bunch of people doing a whole lot of nothing just trying to get from point a to b, I see no logical reason why a "hogwarts express simulator" wouldnt, couldnt or should work... It's all a matter of how much they choose to invest...