I have the Proto 2k 2-8-8-2 Norfolk and Western. I am having troubles keeping the coal tender on the track around curves. I am using 22" radius curves and I know I read a review saying it worked perfect on 18" radius curves. I put some weight in the tender and that reduce the problem but it still will jump the track on curves. The cures are level and it always seems to be the front trucks of the coal tender that derail. Any body have the same problem?