I wonder if this is running wear on the driving faces of the worm and gear. If you look carefully at the worm I'll bet it's worn differently on the face of the 'thread' pushing on the gear for forward rotation. Might be some damage on the driven faces of the gear on the driver wheelset, too, possibly including embedded grit or other contaminants, which might in time cause cumulative damage to the 'new' worm...
cap3344...I know the wheels on the ATSF are pretty squirrely. I then stuck the ATSF onto the back of an Bachmann Loco (doesn't need the tender for power) and it seemed to perform the same in each direction.
It sounds to me like perhaps one of the wheelsets is installed incorrectly, with the non-insulated wheel on the wrong side, but only contacting the rail intermittently, and shorting-out in the same manner.Another issue could be the contact points of the tender trucks to their mounting points on the tender's metal underbody...this is also a problem with brass locos, where they sit unused for some time, allowing oxidation to form. When finally put to use, the oxidation inhibits electrical contact, and the cure is to remove the trucks and polish the contact points - fine wet/dry sandpaper, used dry, works well to clean both mating surfaces.
Wayne
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doctorwayne Trucks are mounted in the right direction, plastic all line up on the same side... but I do like the suggestion regarding the truck contacts. I threw this tender onto another Mantua and noticed the same behavior. I actually tied up a second tender and connected its pickup feed to the ATSF's mounting point and that seemed to work alot better. Going to pull the ATSF apart and take some sandpaper to it. Thanks. cap3344 ...I know the wheels on the ATSF are pretty squirrely. I then stuck the ATSF onto the back of an Bachmann Loco (doesn't need the tender for power) and it seemed to perform the same in each direction. It sounds to me like perhaps one of the wheelsets is installed incorrectly, with the non-insulated wheel on the wrong side, but only contacting the rail intermittently, and shorting-out in the same manner.Another issue could be the contact points of the tender trucks to their mounting points on the tender's metal underbody...this is also a problem with brass locos, where they sit unused for some time, allowing oxidation to form. When finally put to use, the oxidation inhibits electrical contact, and the cure is to remove the trucks and polish the contact points - fine wet/dry sandpaper, used dry, works well to clean both mating surfaces. Wayne
Trucks are mounted in the right direction, plastic all line up on the same side... but I do like the suggestion regarding the truck contacts. I threw this tender onto another Mantua and noticed the same behavior. I actually tied up a second tender and connected its pickup feed to the ATSF's mounting point and that seemed to work alot better. Going to pull the ATSF apart and take some sandpaper to it. Thanks.
cap3344 ...I know the wheels on the ATSF are pretty squirrely. I then stuck the ATSF onto the back of an Bachmann Loco (doesn't need the tender for power) and it seemed to perform the same in each direction.