Hi there im new to model railroading and recently i bought the n scale bachmann left and right crossovers and i ran my engine and it either derails or gets stuck in the middle on both crossovers and when it hauls all my rolling stock its either gets stuck or they all derail i checked for bumps and nothing there and also i switched couplers to medium magnetic couplers and they seem to be installed right so any help would be much appreciated thank you