Light mountain (4-8-2) stalls when traveling over Atlas turnouts

[mikew2]

I have a 4-8-2 that I purchased new last April. It ran just fine originally, but now it "stalls" when traveling over most turnouts.  The stall may be a momentary stop then a restart, or it may just stay stopped.  In either case the stop occurs when the rear truck of the tender is over the turnout frog.  Any ideas whats going on?

[DaveGard]

Sounds like a problem with picking up rail power... probably the loco and maybe also front tender truck.

I had a similar issue with my Bachmann 2-8-0 when it was new... it would more than occasionally stall out when a tender truck was on a turnout frog. I finally pulled the loco shell, and found one of the screw posts for connecting the leads carrying power from the loco chassis back to the tender was not tightened. Tightened it up, and no more stalling!

Looking at Spookshow's loco encyclopedia, it appears the power contacts might have changed in the different light mtn releases... might be from the forward light PCB in early versions (a screw going thru a contact spot on the PCB and into the chassis... that's how it is in the 4-6-0), but the newer release appears to have screws into the chassis anchoring wires with  spade lugs (that's how it is with the recent 2-8-0).

[In principle, the contact wires in the drawbar SHOULD carry chassis power back to the tender, in addition to two of the 6 wires between the loco and tender. But, the drawbar connection is not foolproof... as my stalling issue demonstrated. My stalling problem was exacerbated when I swapped tenders (and decoders) and eliminated the drawbar contacts... then, with the loose screw, I was not getting ANY left rail power from the loco, and it stalled on almost every turnout. Once I tightened the screw, no more stalling.]

You might also check and make sure that the tender truck contact ears are making good contact with their contact strips on the floor of the tender, and of course, make sure you have clean wheels and track.