I run DC not DCC. The one that I have like this has one wire from the motor to the truck. The second one goes from the motor to the frame. It is attached with solder only.so what did the do ? just squirt the caulk in the bottom of the frame? then set the motor in it and let it dry? somebody else said this makes them dcc friendly as well . I`m curious how do they get the ground to the motor so that it runs if that is the case?