Hi every one. I'm having some problems with my Atlas HO 571 Code 83 track 12.5 degree crossing. Some of my cars (all plastic wheels) will jump the rail or rock side to side pretty bad and the new locomotive I got for Christmas will jump the track or have a wheel or 2 jump the track to some degree with every crossing. My 2 GP 40s don't do that and seem to go through smoothly. The new locomotive I got is the A1 OO scale Flying Scotsman from Hornby. What can I do to fix this? Can I modify the existing crossing or do I need to use a different brand crossing? Thanks.