# Bachmann 2-Truck Shay Motor Leads



## Homo Habilis (Jul 29, 2011)

I am converting a two truck Bachmann Shay to RC/Battery using the fabulous RailBoss4 (shameless plug). It is one of the older Shays with the 6-screw trucks.


I was trying to determine which wires go to the motors in the trucks as I do not have access to a wiring diagram for this engine. It is pre-DCC and all I can find are ones discussing the more modern 3-truck versions with DCC.


It appears that the wires are the black ones from the trucks that go to the flicker board. My concern is that when I test one wire to one side or the other of a truck there is always resistance that indicates that a "complete" circuit exists. I'm a bit confused since I thought that one wire would be associated with one side/wheel. But I can touch either side and a single wire and I get continuity. In fact, I can just touch the probes of my VOM to both sides of a truck and still have continuity.



Is this normal?



I certainly do not wish to go up in smoke on this rather expensive engine and board so I'm rather cautious and paranoid. I have already converted a Bachmann Davenport, Railtruck and Gandy Dancer to the RB4 without incident, but those were easy to take apart and locate the actual motor leads.


I wandered the net, reviewing George and Greg's sites among others, and cannot locate any wiring diagrams or discussion of this behavior. The engine ran just fine out of the box on track power so I'm assuming that it is factory wired properly.


Any help or direction would be greatly appreciated.



Thanks, Mark


p.s. Happy Thanksgiving to all, I'm just waiting for the turkey to come out of the oven!


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## Curmudgeon (Jan 11, 2008)

Normal. There are only two wires to each trucks, come off the corner junction on the flicker board. 
You need to pull the bottom cover, pull the wheelsets out, let the ball bearing pickups fly out, check wheels for screw tightness and washer kits, lube and re-assemble. 
Actually easier to do and more reliable electricity wise than the new metal trucks. 
No pins and PC board contact surfaces to corrode, wear, or get a pine needle stuck in.


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## TonyWalsham (Jan 2, 2008)

There are motor connections inside the trucks direct from the pick ups to the motors. 
Remove all the ball bearing picks ups and that will be enough to isolate the loco from the track.


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## Homo Habilis (Jul 29, 2011)

Thanks for the replies. As soon as I recover from effects of yesterday's over consumption I'll rip out the pick-ups as described on George's page.

Thanks again, 
Mark


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## Del Tapparo (Jan 4, 2008)

Good info. I just happen to have a few RailBoss 4's laying around here, and I have a Shay that sorry to say, has been a track powered shelf queen for years. Maybe I'll get around to converting it one of these days.


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## Homo Habilis (Jul 29, 2011)

Del: 

Feeling a bit like the cobbler's children? 

Mark


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## Curmudgeon (Jan 11, 2008)

Here's the more technical aspect: 

Once you pull the bottom cover, you will see a brass buss bar on each side, parallel to the axles. 
They connect the vertical buss inside the housing to the pickups, and at the other end of the pickups is a small 90-degree brass piece with motor leads soldered to said angle piece. 

If you pull the small bridging buss bars, you have no more connection to the motors. This can be fixed by unsoldering motor leads from angle piece, and soldering to the vertical internal buss bars, then fully remove the pickups assemblies. 
Now you have another problem, Sometimes, the vertical pieces are slightly "sprung", and will flex inward and touch the metal motor housing, causing a short circuit. 
This can be repaired by cutting appropriate thickness small strips of styrene, and jamming them between the motor housing and the vertical buss bars. 

Or, you can just remove the ball bearings from the pickup assembly (self-ejecting when you pull the wheelsets straight up), and avoid all the other stuff required to fix a...strange design.


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## Homo Habilis (Jul 29, 2011)

Thanks Curmudge'! 

I've used the technique from George's site regarding just removing the springs. That appears to have worked as the wheels are now dead and the black wires to the trucks still have resistance which you state is normal. It's a good thing that I was born with that third hand so that I could hold, pick and pry the pieces simultaneously! 

I'm just waiting for the battery to arrive so hopefully I'll get to work on it next weekend. 

Thanks again for the advice.


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