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G Bachmann Trolley Chassis Polarity

Started by wm_turnbull, July 24, 2016, 04:12:42 PM

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I purchased one of the "streetcar motor blocks with mudguards" to build into a durable wood trolley for my nephews who already have one of the 4-6-0 north pole sets.  When we put the trolley chassis on the track with the 4-6-0 they both ran towards each other rather than in the same direction. 

So I know one of these is wired reverse of standard NMRA practice. 

I read the schematics for the 4-6-0 set and it indicated there should be a polarity reversing switch behind the smokebox door, but when I opened and looked there I did not find the switch as the photo in the schematic indicated.

I would like to get both of these updated to the correct standard so they can work with any equipment we might add.  I am not in the same town as these trains otherwise I would just run jumpers from my HO track and compare them to my models to determine which one is wired reverse.

Please recommend which one might be wired backwards, I believe it is the 4-6-0, but it does not have a polarity switch to flip, and I don't want to take it apart and reverse the wires if it turns out to be the trolley motor that is wired backwards.

Loco Bill Canelos


I am responding because there have been none so far.  You did not say exactly which locomotive you have, but I can say that the early versions of the 4-6-0 definitely did not have a polarity switch.  The online instruction manual is the later instruction manual for the 4-6-0's which did have the polarity switch.

I know this does not help you identify which unit to change.   My only suggestion is to go ahead and change the one that is easiest to do. Later if you want to add locomotives you can buy one with a polarity switch which will allow you to make it work with what you have.

I do have one caution about building a durable wood trolley on top of the chassis.  Do not make it heavier than the plastic body.  The motor block and the gears were not made heavy enough to carry extra weight.  It is likely the gears will fail if the weight is to heavy.

Good luck and have fun.

Loco Bill
Loco Bill,  Roundhouse Foreman
Colorado & Kansas Railway-Missouri Western Railway
Official Historian; Bachmann Large Scale
Colorado RR Museum-Brakeman-Engineer-Motorman-Trainman
There are no dumb or stupid questions, just questions!


NMRA standard is forward when right hand rail is positive. Garden railway has long been opposite of that.
A.   Direction control by polarity reversing shall be provided. Positive potential applied to the right hand rail shall
produce forward motion. (3)
3)  The term "right hand rail" as used herein means the
rail to the right of the observer standing between the rails
with their back to the front of the locomotive. "
When all esle fials, go run trains
Screw the Rivets, I'm building for Atmosphere!
later, Forrest


Thanks for the responses.
To be sure, I will probably pack one of my HO locomotives with confirmed polarity down to the kids and compare to determine which chassis is running correct.  I suspect the trolley chassis is correct and the locomotive is wired for international/European G direction.  My father in law ordered the 4-6-0 from Hammacher Schlemmeror who buy large lots of goods domestically and internationally to maximize their profit share, so this may have come from further afield.

The wood is 3/8" thick pine, so it is sturdy, but not everly heavy, and actually lighter than the mechanism, which is pretty substantial.  I see this chassis is no longer available from the part store, so there won't be any writing this up into a how to article since no one would be able to get the part needed.

Would love to post a couple pics, but not sure if that will work here.  It just says upload folder full.  The picture is only 128kb, what's the point, this website is looking pretty dated and throwback.  Images that small harken back to the early days of the internet, if I can't upload a 128kb photo what's the point anymore.


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