After wiring up a “new to me” GN engine, with another NCE decoder, I found that the engine ran in reverse when it should have gone forward like my older PCRy engine, (the lower engine in the picture). So I tried the motors in two other Athearn blue box engines, which I acquired two years ago, and they all  turn in the same direction as the newer GN engine motor. Now I have to decide if I want to modify the PCRy engine or all the other three engines. It only takes switching the + and – wires on the motors. I use brass clips on all the decoder wires so switching them is relatively easy.