D & G Models trucks are molded in black styrene plastic. Frames are single piece castings for strength and rigidity. D & G Models trucks have low friction nylon bearing inserts to provide better rollability and longer life. Wheel and axle assemblies are all metal, with one insulated wheel, to allow for electrical pick-up via wipers [not included]. D & G Models trucks are normally assembled with ‘110’ tread wheels, but the narrower ‘88’ tread wheels can be provided if requested at no additional charge. Our experience with the 88 vs 110 wheels is: the ‘88’ wheels are closer to scale for improved appearance. The ‘110’ wheels seem less likely to derail at turnouts and at dips in the outer rail on a curve. Whether these are issues for the individual modeler depends on the quality of trackwork where the D & G Models trucks are to be operated.