I have a problem with Free Roam. Whenever I speed along with an express, a point changes by itself, leading me onto a track with a lower speed limit, meaning that my express will derail from the speeding. It's usually into a siding. And I can't change the point back, no matter what I do. This has happened twice on the East Coast Main Line and four times on the Riviera Line In The Fifties. How do I solve this?