Large Scale Central

Questions on Wiring a 3 Truck Bachman Shay for Battery / RC

So in the spirit of my new philosophy, Use it or Sell it, I pulled a like new Bachmann 3 Truck Shay off the shelf for evaluation. This loco was purchased many years ago from an LSC member and it looks as if he never ran it. I plan to do a RailPro install using only the stock boards so that if I decide to sell it, it will be quick to put back to stock.

The model I have is the DC version, but it supports DCC with a 6 Pin plug and some loose wire connections. The loose wire connections are straight forward and are documented in wiring diagrams. I will only use the Motor + and Motor - connections and just disconnect the Railway R and Railway L connections from the screw terminals to isolate the track pick-ups.

Where I am running into questions is the LED lighting and B+ power connections. Here are my questions…

The front and rear LED lamps are marked on the wiring diagram, as Front LED + and Rear LED +. DCC (and RailPro) normally uses current sinking (switched DC -) to control lights. Did Bachmann label this backwards, or did they just design an oddball DCC board for just this purpose? If labeled correctly, I can use a logic inverter to swap it around for the RailPro output.

Then there is the pin labeled B+. Am I correct in assuming that this is a voltage source for the DCC Board?

And finally, If I leave the Railway connections open, am I correct in assuming that I should power the stock electronics by connecting my battery to the Railway screw terminals as well as my RailPro board?

I’m sure I can work this all out on my own with a meter and a power supply, but in the interest of not wasting any of the Magic Smoke, if someone else has done this, (does not need to be RailPro, just battery - R/C) I’d love to hear your findings / solutions.

If the evaluation proves that this will be a valuable asset for my railroad, I’ll cut out all the stock electronics and wire everything directly to gain more control. As an example, on the stock DCC implementation, the Cab Light and Smoke are on the same wire! The smoke does have an on-off switch in the smokebox.

Say what you will about the “Super Socket” in the K-27 and C-19’s. Bachmann learned a lot between releasing the 3 Truck and the K. everything you would ever want is available at the socket, or in the harness if you want to toss the boards (which I do).

Proceeding very cautiously as I don’t want to fry this thing. Preliminary testing says that Bachman mislabeled the diagram. With the board powered, grounding the headlamp pin lights it up.

With a very little bit of knowledge in-hand, I need to step back and make a good test plan.

Still welcome any input.

Will be watching this thread as I have one to get to eventually. The more details will also serve as input for those that follow.

Will you be installing RailPro, or something else?

My first impression is that RailPro will be pretty easy to install and keep the factory electronics. The down side to keeping the electronics is that remote control of cab light, smoke and flicker is not possible.

If your going with Rail Pro, by the way, good choice, there shouldn’t be much left to fry as all electronics will be removed and discarded for the Rail Pro install. If going with battery power, which would be my choice just remember to remove all track to motor pickups as you will not want these as they can cause havoc and short everything out. Yes, you can run a dual system, but there is plenty of room for a decent size battery and 3-4 hours of run time is plenty for most of us. If all lights are not LED’s then change them to LED’s as the standard bulbs can draw too much current and make run times shorter. I believe I’m seen videos on YouTube on the engine conversion, check there.

Rail Pro does offer several options for control of other engine functions. I do know they have a power outlet on there board for a smoke generator, lighting should not be a problem as there are several accessory plugs for lighting, and as far as fire flicker goes there should be a download from Rail Pro for that. I will say here I only run Rail Pro in diesel engines, so not sure about the fire flicker, but that should be easy to check on. Note here, if you are going battery power you may not want the smoke option hooked up as it will draw a lot of current from the battery. trainman

John -

Thanks for your reply, but you didn’t get the point of my original post and you seem to assume I am new to this. I am not. This will be my eighth RailPro conversion and I have been modifying Large Scale locos for well over 20 years and doing battery-R/C conversions for over 10 years.

I am retaining all of the factory electronics in this conversion so I can evaluate the loco without affecting resale value. My RR has numerous limiting factors that have caused other locos to fail road trials.

Should the loco pass evaluation for acceptance into the active roaster, then I will remove many of the factory boards and wire direct for full remote control.

Bachmann locos don’t need as many modification as many other brands. The lamps are LED’s in a pleasing color direct from the factory and the firebox effect is as good or better than the RailPro flicker effect. There is no need to go through all the work gutting and replacing anything other than the main circuit board where all the wiring comes together. And that will wait until the loco passes all of it’s tests!

Yes I will be doing RailPro with battery and want to leave all the factory boards for future whatever. I prefer to keep the track as an option and plan to attempt to install switch for that like the C-19, etc ability’s. Switching the cab light is not the most critical of functions but would be nice. Smoke is a no go for battery but trying to run it via track as standalone will be my objective. That way any “bad” electrical sections of track won’t show up as a stopper, like it would running the motor off track.

After many hours of prodding with a meter, studying the supplied diagrams and doing various tests I’ve come to a conclusion. It is not possible to isolate the track pick ups without cutting, or unsoldering 6 wires; two running from each truck to the main board. It’s well documented where these connect to the circuit board. If you have a fine point soldering iron and some soldering skills, these 6 wires can just be removed from the circuit board.

If one wanted a track power option, these six wires would need to be connected together by color, then the 2 resulting wires run to a DPDT switch. The other side of the switch would be the battery and the center connection wired to where two of the six wires were removed.

It is possible to drive the motors directly using two wires that are held in screw terminals. This appears to only use the factory electronics as a connection point. The motor wires are routed through the smoke box switch for polarity and on/off, so that switch still functions.

For my test purposes I will not worry about connecting any lighting so I will not need to isolate the trucks. The motor lines do not feed back to the pick-ups when disconnected from the screw terminals, so power will not feed back into the track.

Should you want lighting using the factory boards you would need to isolate the pick-ups as above, then feed battery voltage by taping into to the Red and Black at J2-1 and J2-2. You then need to unplug the 6 pin plug and find (or build) a mate to the wire end. Three wires from that 6 pin are lighting grounds for Front, Rear and Cab. Two are speaker leads that run to the rear tender. I still can’t figure out what the wire labeled " B+ (COMMON) " is for. It has no voltage at all. It might be a way to power the functions on the main board without tying into the track power. I don’t know how to safely test that. I can’t locate any specs for the DCC/Sound board which might give a clue.

Still looking for any input from those knowledgeable in the Bachmann 3 truck Shay.

Smoke 'em if ya got 'em.

Having decided I could only control the motors for now, I set it up with a new RailPro LM-4S-G. Simple set up; battery connector to the Track Inputs on RailPro and the two motor line wires to M1+ and M1-. Played around with start settings and we were off to test around the entire indoor.

The battery is just hitching a ride atop the rear tender while the RailPro LM is stuffed underneath the existing board so the wires would reach…

Road trials went a lot better than expected. On the indoor, my clearances are very close and there is even an industry switch so close to a wall that swing entering the siding can cause a bind. The Shay passed through with nary a rub.

I traversed every siding with no issues and then looked at pulling some cars around. Coupler height proved to be an issue, so for a pull test I cheated with a piece of wire. I couldn’t tell I had added any cars! Lots of power, as expected.

This model was designed when Bachmann was still pairing it with their 1:22 stock, so the stock couplers are very low. So low, in fact, that it will not couple with a stock coupler on a C-19. If it had I would be showing a video of 5 steam locomotives lashed together and I would be sold on keeping it!

Jury is still out, but my soldering iron is at the ready!

Fwiw I love my 3 truck Shay.

Keep it!

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It’s kind of looking that way :laughing:

I borrowed one of the modified drop couplers from my 2-truck. It’s only one screw to remove the truck mounted coupler. The drop coupler mounts in the middle link pocket and is almost perfect match to my standard.

Lashed it up with a C-19 and it played real nice.

Found a Phoenix '97 board with Shay chips in my stash. RailPro’s Shay sound has no declarable speed changes. Stopped or going like hell. RP can trigger a Phoenix plus have it’s own sounds. Need to brainstorm, on that for a few days. I’ve got a few speakers that would fit in the boiler.

The only down side is I have more active locos than I could ever need. That and the market is pretty hot at the moment.

I need a dart board!

Once it’s gone, getting a good clean one back down the road might be iffy. Just something to think about.

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Very true, but at my age, down the road will be a much smaller layout, if any at all.

I’m continuing to play around with this loco. I auditioned the Big Sound '97 board and decided it’s not worth the space it will take up and the complexity it adds to the install. I listened to the RailPro Shay sound again and after a little tweaking, it does in fact change with changing speed. It goes from 0 to 5Mph in one jump, but after that not too bad. I have it in my 2 truck and it’s been OK.

Track trials have continued as well. This thing will absolutely crawl if you want it to!

Today I dug into the third truck tender. One of the huge magnet speakers that came from Ken’s estate will fit in the opening, but makes the remaining space about 1/4" too shallow for a battery pack. I could shift the speaker a little and it wouldn’t hurt anything.

With speaker, battery and control in the third tender, I would repurpose most of the wires in the tender plug and only use the factory electronics as a power source for the lighting and flicker.

And speaking of that third tender; I think it’s kind of odd that the tank and the truck are completely stiff, no flex at all. Any bumps in the track are exaggerated by the tank. It also seems to be set back too far. I recall reading TOC or George S. saying that a close couple option didn’t work well. I need to look that up.

When I was doing my reverse engineering tests I did not want to cut off the 6 Pin plug in order to confirm operation of the circuits it interrupts. I looked around for the mating socket, but could only find it in PC board mount. I figured if I was going to need to solder wires anyway, I might as well just make my own mate.

I stared with some header pins I picked up from Amazon for my servo driven switch project. The pins are spaced identical to the Bachmann plug and they can be cut to the needed number of pins…

I had some 4 conductor ribbon cable left over from my RGBWW lighting work that got soldered to the pins. I needed 6 wires so two more were added…

To protect from shorts, a few layers of heat shrink finish it off,. The white dot is for polarity reference…

Electrically, it does this. Adapter on left, Bachmann plug on right…

Does the factory pigtail board from Bachmann have any other circuitry on it?

From what I could figure out, the board in the front bunker is primarily a junction point for all the wiring, but also contains circuitry to drive the lighting from a DCC decoder or similar like RailPro. When running track power it also handles the directional lighting. I couldn’t see any reason to chuck it.