Strange Development with Ultimate Terrain Canada/Alaska

Any movement to the area covered by UT Canada/Alaska developed into a crash to desk top, whether by choice of airport, slewing or flying into the region.It has been some months since my installation of UT Canada/Alaska followed by UT USA. It has also been some weeks since I flew this area, so I really don't know when the problem developed. In past times, I have flown this area all the way across Canada with no problem. I have also had no problem with extensive flying throughout Alaska. I disabled UT and went back to default scenery and there was no problem. By process of elimination, I found that in the UT Canada/Alaska Setup Utility, if I had Enhanced Railroads checked the crash to desktop occured. All other options seem to work fine in whatever combination is desired. Obviously, this option is in conflict with something somewhere.In UT USA, either with Enhanced Railroads checked or unchecked everything works fine throughout the USA.Has anyone else experienced this problem, or know a solution?Thanks:RTH