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Set up a Marx train set

If you’ve lost the original instructions, it’s certainly not obvious how to connect a Marx transformer to track and otherwise set up a Marx train set. Especially if someone else always set it up. But don’t be intimidated. It’s low voltage wiring. And it can be as few as two connections. Here’s how to set up a vintage Louis Marx electric train set.

Safety first

Before setting up any Marx train or any other electric train, give the transformer a visual inspection at the very least. Make sure the power cord isn’t frayed or broken and the case is intact, with no breaks or cracks. I have a more thorough safety inspection I put transformers through. If your transformer isn’t in good condition, lots of professionals refurbish transformers and sell them on Ebay at reasonable prices. If you’re not sure what to get, here’s some advice on how to choose a Lionel transformer. (Lionel transformers work fine with Marx and can be easier to track down today.)

There is a misconception that old transformers are unsafe to use. Transformers don’t go bad just from aging. Consider your doorbell, for instance. That uses a transformer. The doorbell in my house, built in the early 1960s, still uses the original transformer the builder installed. It’s never been a problem. Sure, that’s anecdotal. But I have a good relationship with my realtor and house inspector, and they tell me that’s typical. Even on houses dating to the 40s and 50s, it’s more unusual to see a replaced transformer than the original.

I also like to test the track. Troubleshooting is much easier if you start out knowing that all the track is OK.

Connect a Marx transformer to track via a lockon

Connect Marx transformer to track

Here’s how to connect the Marx lockon to a piece of track. This is an essential step when setting up a Marx train set.

Louis Marx electric train sets shipped with O27 tubular track. It connects to the transformer with a lockon, a small fiber board with contacts that snap into the underside of the track, and two wire terminals. The lockon connects to your center rail and one of your outer rails. I always connect the lockon so the terminals sit outside the loop of track. It’s easier that way, since the transformer usually sits outside of the loop.

The lockon has two contacts that connect to the rails on your track. They just snap into the small gap in the underside of the rails. One goes in the center rail and the other goes into the outer rail. Just line it up with the two rails, then press it together. It works a little differently from other brands of trains but the design was relatively reliable. Properly installed, it looks like the image to the right. Connecting it any other way results in either an incomplete circuit or a short circuit. You don’t want that.

connect Lionel transformer to track

The wires connect to the lockon via Fahnestock clips like this one.

Then you connect your wires. I like to use black and white wires of at least 18 gauge. You’ll probably use whatever wire you have in the box. Make sure it’s not frayed and the insulation isn’t broken. And as long as the wire doesn’t feel hot when you’re running the train, it will be OK.

The lockon has two terminals, called Fahnestock clips, that wires connect to. These are spring loaded, and when you press down on the spring, you slide the wire into the opening, and then release. The spring grips the wire and holds it in place. Twist the wire so it fits the opening, and just ensure it doesn’t contact anything other than the clip you inserted it into, to avoid short circuits.

On the transformer side, the wires connect to screw-on terminals. Loop the wires into a C so they stay on the terminal, and tighten the nut down onto the wire to hold it in place. Here’s a more thorough explanation if that part isn’t completely clear.

The terminals on the lockon and transformer may be labeled. If the Marx transformer has two posts, just connect them to the track. If the transformer has four posts, one will be labeled for accessories. Use the other one. Marx trains don’t care much about polarity, but here’s how to find the common post on the transformer. By the book, the common wire goes to the outer rail and the hot wire goes to the center rail.

But don’t worry too much. If you get it wrong, the worst that can happen is that your train runs at one constant speed.

Connecting additional lockons

If your train runs at inconsistent speeds, you can connect multiple lockons to the track. Just make sure you wire them all consistently. Here’s how to add lockons to the track. But keep it simple at first. Get the train working with one lockon and one transformer connection first, then add lockons if it’s necessary. Tracking down Marx lockons is difficult these days but a lockon from Lionel will work.

I’ve also found that treating my track so it stays clean also makes the trains run at a more consistent speed.

Connecting track

The track plugs together easily. There are pins in one side of each track section and holes in the other. Simply plug one section into the next to make a circle or oval of track. Louis Marx electric train sets usually came with enough track to make an oval. The holes in the track ties facilitate mounting the track on a piece of plywood. This is optional but I really recommend it for a permanent layout. I use size #4 wood screws.

If the track doesn’t hold together on its own, you can secure the ties of adjacent track sections with small rubber bands.

Putting the train on the track

The other thing you want to do before putting the train on the track is to make sure the wheels on the engine and the track are reasonably clean. They probably won’t be bright and shiny after all these years, and they don’t need to be, but they do need to be clean. The most frequent reason a marks train won’t run when you first pull it out of storage is dirty drive wheels.

To clean the drive wheels, dip a cotton swab in a bit of rubbing alcohol and give each wheel a light scrubbing. The flat underside of the wheel and the flange are the most crucial.

Then do the same for the track. I find a paper towel easier than a cotton swab, but once again, wipe the tops of the rails with a paper towel with some alcohol, and if you want to be really thorough, wipe the inner portions of the outer rails where the flange meets the track for good measure.

With that bit of preventative maintenance out of the way, the locomotive should fit easily in between the outer rails. Make sure all of the wheels contact the outer rails and the locomotive rolls freely. Then connect each car. Here’s a primer on Marx couplers if you need it as they varied over the years.

Once you have the train on the track, plug in the transformer and turn on the power. Start slow. If the train doesn’t run, here are some tips for troubleshooting Marx locomotives. They were designed to be easy to fix.

And if you have some accessories such as lights or a station, here are some tips for wiring the accessories.

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