Large Scale Central

The RC Thread w/Pics for Timmy

You may have seen Timmy’s recent posts about trying to convert a loco to rc/battery. He asked if anyone knew of a thread with photos that could guide him through it. No-one responded - I certainly couldn’t remember any such thread on MLS or LSC.

I recently acquired a Hartland 4-4-0 for my Civil War train
and as I had a complete Cest Revolution system that had been removed from a C-16, and as I was planning to go to Jim K’s track to show Jack the Civil War train, and as Jim has no track power, it seemed like a good idea to convert the 4-4-0.
And while I was at it, I could take copious photos for whoever asks next time!

I will try to be as general as possible, but as the saying goes, your mileage may vary. This is a tender conversion, which gives you a bit more room than trying to cram everything into a tank engine. A diesel is usually easy as there is plenty of room.

First, the basics. Track power - remove or modify?

The Hartland 4-4-0 has nice driving wheel pickups, and one of the tender trucks also picks up power. I decided to use just the tender trucks and to isolate the loco wheels. That was pretty easy to do, by removing the screw in the middle of the wheel, levering the driving wheels off with a flat screwdriver, and pulling the brush and holder out of the chassis. Then put the wheels back carefully.

Other locos may need you to dismantle the engine and get at the motor in order to isolate the track pickups. Some LGB locos have plugs with wires on the ends of the pickups that you can pull off, after opening the bottom of the loco. Almost all of them are a little different in design.

I got out the components to photograph and labelled the pic.

I am using 2 switches - one for the main On-Off/Charge and the other for Track - Battery. They don’t need to have a center-off option, as turning the main switch to Off kills everything and lets you plug in the charger. Most conversions like this don’t need a track-battery switch so consider it an option if you have tender pickups.

The battery is a brick: 4x 18650 cells arranged in a rectangle (2x2.) I think it was sold for a robot floor cleaner. You can also get double size batteries, with twice the cells and twice the capacity, in either a brick or a flat pack.

A note on the Crest Revolution throttle I am using, which has a small add-on board with connector blocks, and a lot of wires, left over from the C-16 where it was used.
The little connector board provides power in from the battery and power out to the motor. The other connectors are for headlights, etc., which I didn’t use.

The wires that you see all curled together consist of

  • Speaker connection wire black/white pair with big red plug on the end,)
  • Binding switch (red push button, which you use to tell the board to go into bind mode and listen for a transmitter signal. When it finds one, it ‘binds’ itself and expects that transmitter to send it commands.Hidden under the board.)
  • Chuff trigger wires.
    The chuff trigger is not strictly necessary - these throttles will chuff quite realistically based on the speed you tell the loco to go. I like them so this loco is getting one.

I use a 5.5mmx2.1mm power plug and socket, as they are standard in the LED strip business and therefore available quite inexpensively. If you haven’t had much experience with Lithium batteries, then get a decent charger, like the Tenergy one:

If you have one of those, then there are some chargers that are much less expensive for backup; even has a red/green LED:
(Just make sure you get one with a US wall plug, and the type for your battery. 14.8VDC LI batteries charge at 16.6V.)

Then I turned to the tender and removed the trucks and the 4 screws from underneath. [Most tenders come apart that way - either screws underneath or hidden somewhere on top.] You may have to disconnect wires from the trucks if it has pickups - the HLW truck wires stayed underneath and came away with the truck, so it was easy. There may also be a wire to the rear lamp, or to the rear power sockets, so you will have to decide what you are going to do with them.

As a general comment, adding RC is just substituting power to the motor from the on-board throttle board, instead of collecting it from the track. The lights should continue to work as they did, unless you want to change them - swap the bulbs to LEDs (automatic directional operation,) or make them controllable by the throttle electronics.

This tender has room for everything and is a sealed box, which is good!
I also taped some styrofoam underneath to protect the steps, whcih protrude underneath. You can imagine that working on the tender floor is going to put strain on them unless they are protected.

and now we can start figuring out where everything is going to go.

Here I am juggling the components, to see whether to put the battery in the back and the speaker in the front, or what. The tape is useful for marking center-lines, etc. The final arrangement of pieces was/is much like you see here.

I decided to fit the speaker in the front, as there are several bits of bodywork that get in the way of a battery. It was pretty easy to Dremel some of the walls to make the speaker fit as far forward as possible.

One issue to be aware of is that the speaker will sound much better if you enclose the rear side of it, so the sound from the back doesn’t interefere with the sound from the front. I did cut a wall to isolate the speaker:

but decided it wasn’t needed as the tender shell is solid and will form a box when screwed down. Lots of tenders have open tops, or holes for this or that, which upsets the sound.

Then I taped over the floor and starting planning the holes for the speaker sound - the floor was solid. Here I had drilled pilot holes to guide the bigger 1/4" holes.

Then speaker was then fitted on the front. The conventional way is to clamp it with some screws, as you see here. You might also notice the tiny bolt head - the prior owner used 1.6mm bolts all around the circumference of the speaker. I used a few, and added the screws for safety.

Great write up Pete.


Having figured out where the major components were going to fit, I looked at the controls. This pic has the holes for the 2 switches (yellow arrows) and the charging jack (green arrow.) The holes I drilled for the speaker are visible.

Here’s the switches mounted, from the inside.

I then counted how many other holes I’d need - one for the battery monitor, which is going underneath. One for the track pickups to the track-battery switch, and then back to the motor in the loco, and then one for the wires for the chuff trigger.

Now to fix the other major item - the battery. I had always intended it to be strapped in place, so I went looking for a strap - and found a piece of brass strip the right size, and (surprise) it had holes in the right place.
I also added a couple of plastic blocks to stop the battery moving sideways. A derailment can cause a lot of issues if things are loose!

And here’s the main components ready for wiring.

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A few minutes to add some wiring to the tender. This is the main power to the throttle.

Two big thick wires from the battery go to the center terminals of the ON-Off-Charge DPDT switch. [Yellow arrows.]

Two wires from the LH side of the switch to the charging socket. [Green arrow.]

Four wires from the RH side of the switch. [Purple arrows.] Two to the Revo add-on board, visible top left. And connected to them are a pair of wires to the battery monitor under the floor, but they aren’t visible.

The power wiring is pretty common for any type of throttle - you need to charge the battery and turn it off.

Here’s the battery monitor, underneath so you can see it whe you turn on the power.

Cost $0.79, but the jury is out on whether it works, as I’ve only had it for a few weeks!

A slight modification, and an apology. I forgot to add the fuse to the original picture of the components. It was sitting at the side, and I decided to install it.

Those 2 orange square things are “Polyfuses”. They work just like a regular fuse, but reset themselves after the problem goes away - much like a thermal cutout on an (old) power pack. These are 2A each, and can be attached in parallel to gain as much fuse protection as you desire. So I have protection for spikes over 4 amps.

You could leave the fuses out. Your battery will have a BMS (Battery Management System) pcb inside the wrapper, and it will prevent damage to the battery if there is a short-circuit. The issue to be aware of is that Lithium batteries can produce a high current (amps) for a short period [which is why they are used to jump-start a car!] The BMS will limit the current, but probably to 10-15 amps! That’s a lot for us - most large scale motors pull about 2 amps max. So if you have a short circuit, those thin wires could melt before the BMS decides the battery needs to be protected.

I have another, similar rig in a tender that I acquired by accident, and it has an auto-type fuse sticking out underneath. (Which was a silly idea, because it isn’t mounted in a fuse holder, so you can’t just pull it out and insert a new fuse.) However, it works to protect the electronics. Another option is a regular glass fuse in a fuse holder.You can buy fuse holders designed to be used in a circuit at your local auto parts store, for modern or old fuse types.

So, moving along, the next process was to install the Crest Revo throttle (or the DCC/RC throttle of your choice.) I stick them down with double-sided foam tape. Here the tape is in place but the top strip needs removing so that I can press down the throttle onto the tape.

Once the throttle is fixed, I added the wires from the motor output. (Blue+White in this next photo.) If your tender has no wheel pickups, then the motor output would go straight to the front of the tender to a plug which would carry the power to the motor.
In my case, I do have wheel pickups on the tender, so I have a DPDT switch that supports Track or Battery operation. The center of the switch will go to the motor, and one side is the throttle output, the other will be wired to the trucks.

I haven’t really discussed the placement of the various bits, except in the short mention of where the components will go in the tender in my first posts. But clearly it all has to fit inside, so what you haven’t seen is me test-fitting the tender top at each step to make sure everything still fits.

I spend an hour or two yesterday wrestling with the undercarriage. Most of this work is not necessary for installing RC/battery or DCC/Battery, unless you want to use a Track-Battery switch option.

Here’s the pair of trucks, and one has the wheel pickups, which is why I decided to add the track-battery option. The little plug on the bottom/front truck is the existing connector to the loco. I had to cut those wires as they go direct to the pickups, and I had to splice in more wire to the track-battery switch.

I added a pair of wipers from a Bachmann coach truck, which I think are phosphor-bronze. I originally planned to make some from phosphor-bronze wire [phosphor bronze is springy, doesn’t corrode, and is a good conductor. You can buy sheets on Amazon - I got the wire from a trolley vendor 30 years ago.]

The screws for the track pickups protrude, and I had to remove them with a Dremel cut-off, as the chassis rests right there on the truck! You can just see the curved marks.

I’m also adding a ‘chuff’ trigger, so here’s the clamps holding the tiny magnets while the glue sets. The tender wheels are almost 1/2 the size of the driving wheels, so 2 magnets should give me 4 chuffs (approx) per driver rotation.

And this is the reed switch being installed and wired. It’s at an angle, as it is very sensitive, and I found that it would trigger twice if it is too close to the magnet.

So there are a total of 4 pairs of wires from the underside to the inside of the tender on mine:

  • pickups from the front truck to the track-battery switch
  • pickups added to the rear truck to the track-battery switch
  • motor feed from the track-battery switch to the front of the tender
  • reed switch wires to the chuff trigger port on the Revo throttle.
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And then I found a real problem, which I had not anticipated (my bad.) This is a short tender, and I hadn’t checked wheel clearances underneath.

As you can see, the switch hits the truck! So I had to swap the charging socket and the switch (grrr . . . ) and move the track-battery switch on the other side. I also had to move the battery monitor, and rearrange some wires. All unexpected work, but my own fault for not thinking of checking first.

You know what they say: measure twice and cut once. If I did this more often, I might remember to check!

I moved what had to be moved, and reattached the trucks. I then finished the wiring of the track pickups, etc. The blue-white wires go to one side of the switch from the throttle, and there’s another blue-white pair from the center to connect to the plug in front that fits the loco. The back of the switch has the 2 pairs of wires from the 2 trucks’ pickups. The pair of wires on the left are the chuff trigger pair connecting to the back of the throttle.

I think that’s just about it. Do I need to add a wiring diagram?

If you take a look at the Ops thread for Jim’s Nov 18th session:
you will find a few photos of the 4-4-0 running up hill and down dale on Jim Kottkamp’s layout.

In the final analysis, that speaker is way too big and produces too much sound (if that’s possible!) I’ve ordered a few smaller speakers to cut it down a bit.

Here’s the wiring diagram I created for another thread:

And the speaker has been replaced with a smaller one!


Being somewhat isolated from club meetings and fellow gardeners who share my passion for running trains, I frequently turn to the LSC FORUMS in search of answers to my questions. Exploring various opinions on project approaches reveals the richness of multiple perspectives.

Yet, there are moments when I don’t have a specific question and stumble upon a thread like yours. Reading through these discussions, I’m often in awe of individuals who’ve dared to break the factory seal, performing operations on rolling stock that elevate their garden railways beyond the original design. While the technicalities discussed may be over my head, I can’t help but feel that such feats are beyond the scope of my abilities.

I appreciate that BD is considering a summer solstice MasterClass. Threads like yours, serving as comprehensive “how-to” guides from start to finish, have the power to inspire individuals to embrace challenges beyond their perceived skill level. Imagining an LSC page dedicated solely to MasterClasses, your thread is exactly what I’d hope to discover when the time comes to upskill beyond my current capabilities.

Hmm, that sounds familiar. :thinking: :wink:

Thanks for the kind words, Bill. :slightly_smiling_face: