Large Scale Central

Working MU Connection

Putting this under another heading so that someone who may have done it will see it that may not have seen my other post. I hope we can come up with a reason looking plan.

So I want to MU (I guess that really is the right term) two USA GP9s. My vision is for these locomotives to ALWAYS be paired. I realize I may regret this decision at some point. But the prototype always runs two low nose GP9s together long hood to long hood. They keep them together almost always themselves. They even park them in the barn this way. I asked onetime why they do it even when pulling small loads. The reason is so they do not have to turn locomotives they can just simply swap ends of a train and jump in the other cab. But whatever their reason they always have two together and always long hood to long hood.

For this project then I would love to make one locomotive hold all the electronics and the other hold the batteries and have them permanently wired together. I realize I can do this somewhat generically by just running wires between the two in a bundle. But isn’t that what they really do with the MU cable. So why not try and make a MU cable in the right spot and be at least somewhat prototypical. If I can’t I can’t but I am hoping the talented minds here have an idea. I do want them both powered. So its more than just battery wiring. I would need throttle control and ultimately lighting control that lights up the forward locos cab and headlight when its the front loco.

Devon Sinsley said:

Putting this under another heading so that someone who may have done it will see it that may not have seen my other post. I hope we can come up with a reason looking plan.

So I want to MU (I guess that really is the right term) two USA GP9s. My vision is for these locomotives to ALWAYS be paired. I realize I may regret this decision at some point. But the prototype always runs two low nose GP9s together long hood to long hood. They keep them together almost always themselves. They even park them in the barn this way. I asked onetime why they do it even when pulling small loads. The reason is so they do not have to turn locomotives they can just simply swap ends of a train and jump in the other cab. But whatever their reason they always have two together and always long hood to long hood.

For this project then I would love to make one locomotive hold all the electronics and the other hold the batteries and have them permanently wired together. I realize I can do this somewhat generically by just running wires between the two in a bundle. But isn’t that what they really do with the MU cable. So why not try and make a MU cable in the right spot and be at least somewhat prototypical. If I can’t I can’t but I am hoping the talented minds here have an idea. I do want them both powered. So its more than just battery wiring. I would need throttle control and ultimately lighting control that lights up the forward locos cab and headlight when its the front loco.

The previous version MacBooks used a magnetic power connector. Something like this

https://www.amazon.com/HytePro-Magnetic-Connector-Connection-Electronic/dp/B07R7GGVDP

Aliexpress has this single contact one.

https://www.aliexpress.com/item/1005002065465508.html?spm=a2g0o.productlist.0.0.240f5600KAvVfu&algo_pvid=f3faba73-933d-4d2c-9a9f-b6784dae67b6&algo_expid=f3faba73-933d-4d2c-9a9f-b6784dae67b6-11&btsid=0b0a556116158243316228563eb645&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

Devon,

Next winter I plan on doing a GP9rm with a slug, and plan to do the same thing. Luckily, in my case, the units have big electrical boxes where the slug cables plug in. I plan on making those connections real.

It might be hard for you to get all the wiring you need into a realistic MU cable. It may be easier to make that fake, and set up your 6 MU hoses as electrical connections disguised as hoses. Maybe you could find some micro sockets and plugs and you could make a fake gladhand connection in the middle of the wire. Set up one unit with the wires/cables, and the second with the sockets.

I’m sure others will share some ides.

Shane

Now that is a great idea Shane. You are thinking like I am thinking that I am going to have too much wire to make it realistic. But a combination of using the MU connection and all the air hoses is a great idea. Sockets would be nice mainly if I have to make repairs then they are easy to disconnect but I could trade off ease of disconnecting for a more authentic looking connection. Like I said these will be permanently attached. I am a steam guy so this one Dismal consist will be just that a stand alone prototype specific train. So I can get away with them being hard wired.

Bob,

Those are interesting. Not sure if I can make it work as a authentic looking MU coupling but what I like is the fact they are a magnetic connection. One problem I have with my hair brain idea is having the two locos hard wired only from a maintenance stand point. If I need to fix one then I have issues taking them apart. Hence why I wanted a MU cable. Now sure they make all sorts of connectors but I like those magnetic ones.

Okay help me further think on this. How many wire are we talking between locomotives. The limiting factor is operation of the battery loco. So the bat loco needs to have a pos and neg sent to the control loco. The control loco needs to send back motor control and lighting wire for “reverse”. The two long hood lights will never need to work. So when the locos go in “reverse” the front light of the Bat loco comes on and in “forward” the front light on the control loco comes one. Cab lights will be wired to the headlight so the same cab light is on as the front light. Step lights can be wired in each loco straight off the battery so that when the loco is switched on the lights come on. Sound will be an after thought. I don’t run sound now and if I do run sound do I really need both locos to have their own sound or is one sound good enough. Thats what I am thinking.

Now things like the motor control and lights normally have - wires returning to the board. Is there a reason from a control board point of view for this. On a car the only thing that matters is the + wire. Everything else can be grounded where ever there is a common ground such as the frame or??? Can I have the motor control lighting ground wires attached to a common ground at the battery negative terminal? If thats the case then I would only need four wires instead of 6. + and - from the battery, + for motor control of the bat loco, and + for the lighting to the bat loco.

I will test all this out ahead of reinstalling it all to see if it works the way I think it will unless someone can positively say no you can’t so it that way. But four wires is managable and I think I can make that look pretty well disguised using the methods above.

I don’t know (I could be wrong about this), but I remember somebody doing this about 15-20 years ago for the 1:20.3 modelers. An actual vendor :). In fact, I believe I have 6-7 sets buried somewhere in my storage of my 1:20 “stuff”. They had cast bronze glad hands with a very tiny magnet embedded in the casting.

I will have to look and see if I can find them in my stash. I have been doing 1/8th scale ride-on trains for the past ten years, so I have lost track of much of my 1:20.

I purchased a mini plug connector kit from Amazon, something like this one, but there are many to choose from there. https://www.amazon.com/Glarks-1191Pcs-Housing-Connector-Compatible/dp/B07TB8QXMC/ref=rtpb_19?pd_rd_w=HTchl&pf_rd_p=be844577-fee7-4bbc-8dda-083e56cc6f0d&pf_rd_r=RN3FPXFVSWZWVZ62B5WA&pd_rd_r=26767681-7599-497d-b41f-ee4cba5ef9c0&pd_rd_wg=WDdgD&pd_rd_i=B07TB8QXMC&psc=1 I find these small and work out very well for connecting my engines and tenders, plus I use them for many of my RR projects. They are small and in your case I might take two four plug sets and put one on each side of the coupler, thus giving that MU look you are looking for. The color coded wires can be split into any configuration you want and then painted black to look like MU’s. The plugs can be mounted up under one of the engines and you will never see them, but can be unplugged when needed.

trainman

One concern i might have is the physical connection between the two locos, from the stand point of operation and handling, derailments, etc. Permanent connections like a draw bar would keep the engines together in the case of a derailment and protect the interconnect wiring. But that would be difficult if you want to pick them up.

If you choose to make them so they can be seperated, wiring connectors would be required and they should be easy to plug in CORRECTLY as well as being flexible , tough and seperate cleanly in case of an accident.

Devon,

What brand decoder and sound will you be using? I’m not sure about a common lead for the motor since it reverses polarity with direction. I do think a common lead for lights would be easy.

I will be using Revolution train engineer. But good call on the polarity. Hadn’t thought of that. So likely needs its own ground.

As Eric mentioned and I mentioned I will likely make them plug in and not be hard wired. Even though I will run them together there are reasons to separate them. So its a matter of hiding 5 wires if I count correctly.

Bat +

Bat -

Motor +

Motor -

Lighting +

Even if I need a Lighting - I think the idea of using the glad hands is a good one. I am almost certain that Precision Scale Company has working brass glad hands and valves that connect with rubber tubing. If that’s the case I am sure with a little finagling I can use solid stand communication (or some other small gauge solid wire) wire and run it through the hose and solder onto the valve and glad hand. Since they are working they make a positive connection. Might even be able to use the wires insulation as the hose. Since there are what three hoses on each side of the coupler that would give me a whopping 6 connections. Any reason why this won’t work?

I’ve done it, but it was never as sophisticated as you are planning. I let the original loco wiring handle the lights and just fed motor output to the lead loco’s track pick up connection. I did sound too. I used one two-wire JST SM-2 connectors (same as Aristo Power plugs) for the motor line and a SM-3 3 conductor for the sound. Hid the wires in black shrink wrap to kind of look like hoses. No where near as pretty as what you have envisioned. Here is the front of one loco that was set up for M/U…

Power on the left. So I didn’t need to worry about plug polarity and allow either end to be an MU connection, I used that short double female between locos. Ugly, yes.

Jon,

What I envision and what might actually happen could be two very different things. My dad always says want in in one hand and poop in the other and see which one fills up first. So I put my dreams out here so people can bring me to reality. But I am really hoping the glad hand ting works. But if not mine will look a lot like what yours does.

Devon,

I guess I really missed the whole point of your question :). What else is new?! I was talking about actual working glad hands that attached by magnets and would detach from the train during switching (per prototype).

There are real working glad hands and hoses for working train brakes for the 1/8th scale ride-on trains. But these are tiny even in THAT scale!

Good luck with your project>

Yep. I’m that way too. If you want to keep it simple, put a Revo in both and batteries in only one. Then you only need to extend the battery power. Set up your Revo MU just like you would two autonomous locos. That way, if you ever wanted, you could run the loco without batteries either on track power (needs a switch) or with a battery trail car. With only two wires to extend, making glad hand hose connections might be doable.

Gary Armitstead said:

Devon,

I guess I really missed the whole point of your question :). What else is new?! I was talking about actual working glad hands that attached by magnets and would detach from the train during switching (per prototype).

There are real working glad hands and hoses for working train brakes for the 1/8th scale ride-on trains. But these are tiny even in THAT scale!

Good luck with your project>

No I think you got it. The ones I am talking about don’t use magnets but they lock with a 1/4 turn like the real deal. So they do lock and unlock during switching. Just doesn’t use the magnet as you are saying. they are not working in the sesne of providing real air, just real connecting. So I think you were right on top of it.

Gary Armitstead said:

Devon,

I guess I really missed the whole point of your question :). What else is new?! I was talking about actual working glad hands that attached by magnets and would detach from the train during switching (per prototype).

There are real working glad hands and hoses for working train brakes for the 1/8th scale ride-on trains. But these are tiny even in THAT scale!

Good luck with your project>

Those were from Geoff Ringle. I have a bunch of them. It never worked out well for me connecting them, but with careful attention to length, they did work. I still use them since they look great, but rarely attach them. It might be possible to electrify them as a single conductor connection. Trouble would be soldering to the white metal casting.

Jon Radder said:

Yep. I’m that way too. If you want to keep it simple, put a Revo in both and batteries in only one. Then you only need to extend the battery power. Set up your Revo MU just like you would two autonomous locos. That way, if you ever wanted, you could run the loco without batteries either on track power (needs a switch) or with a battery trail car. With only two wires to extend, making glad hand hose connections might be doable.

I am just being cheap. I was hoping to get away with not buying two ESCs. But if thats what I end up having to do then thats what I have to do.

Jon Radder said:. Trouble would be soldering to the white metal casting.

This is why I want to try using the Precision Scale ones because they are Brass/Bronze. I should be able to solder the wire to them. It will be a fun experiment to see if it works. 6 brass glad hands should give me 6 single conductors if it works. And my plan is to not have to disconnect them often. Ill make a cradle to carry them attached

Gary inspired me to dig out my stock of Geoff Ringle’s Old Iron Designs Proto Hands. They are not white metal, but cast nickle silver. They will take solder and are a good conductor.

I did a quick low voltage test. One leg of a 12V LED circuit running through a pair of glad hands. The LED lights up and even if I move the hands around, it doesn’t flicker. I don’t know what the current capacity might be, but they just might work for you!