I bought a blue box loco at a train show. To get the locomotive to move I have to apply full throttle and then cut it back. The engine will hum prior to moving. I oiled the bearings on the motor, cleaned and re-greased all of the gears, cleaned the wheels. I did notice that there is allot of play in the armature from front to back of the engine. Short of replacing the motor I am out of ideas. My power supply is an MRC Sound and Power 7000. My son's Bachmann supply does not even have enough juice to start the loco.