I have an N Scale Athearn SD-70 that has a Mashima motor in it. Randomly, the locomotive will stop, with the lights and sound still on and running (I installed a DCC sound decoder in it). The sound or lights do not go out; the locomotive just stops. With the power still applied, I remove the shell, and use a rubber eraser from a pencil to move the flywheels, and the motor seems like it wants to go but it seems like torque is not there to move the gears. I remove the locomotive from the track and move the flywheels, and the gears turn freely. There is no debris or lint holding up the gears in each truck. I thought that Mashima motors were good. What's going on? Anyone know how to oil the bearings or internal parts of the motor without actually removing the motor from the frame? The motor is getting power (as proven by the fact that the motor will spin about 1/20th of a full revolution when I use a rubber eraser to turn the flywheel and that I can hear the electrical growl each time I do that), so that tells me it's not a problem with the decoder OR power electrical pickup.