How to fix old Marx locomotives

I’ve been noticing that a post I made several years ago about my experiments fixing a Marx 490 train locomotive has been getting a disconcerting number of hits. Disconcerting, because I repeated some advice on how to fix old Marx locomotives from another web site that I later found, by experience, wasn’t all that good.

Here’s how I go about doing simple repairs on Marx trains today, now that I’ve done a few.

First things first: If you need help getting your train disassembled, I have specific advice on the Marx 666/1666, the Marx 490, and the Marx 999. The advice for the 999 applies to most other Marx trains out there.

The next order of business, once you disassemble it enough that you can get to things, is to clean it up. Contrary to some advice you find elsewhere online, WD-40 isn’t what you want. Spritzing a motor down with WD-40 does indeed get rid of a lot of dirt. But the residue it leaves behind just creates another problem. If it gets into the brushes and onto the commutator, the motor won’t run.

Fortunately, as long as all of the parts are there, you can clean the motor up and re-lube it, regardless of what any other tinkerers may have tried in the past. These motors were extremely durable, so they almost always respond well to this treatment.

CRC zero-residue contact cleaner
CRC zero-residue contact cleaner is a tonic for most of what ails old toy locomotives

Zero-residue CRC Contact Cleaner is perfect for the job. You can spritz the motor with it without even disassembling anything. Just spray it down, avoiding the bronze bearings around the axles, set it in a tray, let the accumulated crud of ages past run out. Then, if it doesn’t look completely clean, repeat. Avoid spraying the bronze bearings because they have lubricant impregnated in them.

Some sites recommend Radio Shack tuner cleaner. The CRC cleaner is better and cheaper, and much more readily available.

Spray some on the wheels too, as they’re a critical part of the electrical path. If that doesn’t completely clean the wheels, a cotton swab dipped in some of the CRC cleaner or some mineral spirits will help.

If there’s a large kraft paper-covered assembly at the front of the motor, that’s the reverse unit. It’s a clever design but if it gets dirty or sticky, it causes problems. Turn the motor over and spray some of the CRC cleaner up into that assembly as well. Pick up the motor and shake it back and forth a few times to work the cleaner up into that assembly, then flip the motor over to dry.

Now, hurry up and wait. Let it dry thoroughly; 15-30 minutes should be adequate. I have advice on repairing reverse units if spraying it down doesn’t work.

Check the pickup shoe on the underside of the locomotive and make sure it’s clean and doesn’t have any spots worn through.

Look at the copper sliding pickup shoe on the underside of the motor, and make sure it’s clean. If it’s worn through, you’ll need to patch it by soldering a piece of sheet brass over the gap. A quick temporary fix that sometimes works is to remove it, flip it around, and put it back on, since the wear tends not to be dead in the center.

You should also examine the wheels. Since many of these spent time running on a loop of track on the floor, there can be hair, carpet fibers, and other similar debris wrapped around the axles. If you see this, about all I can say for this is to reach in with a pair of tweezers and pull out what you can. When you can’t tweeze any more, slice at the debris with a utility knife. Sometimes it turns itself into a Gordian Knot and the only way through is to cut it.

If the motor has a felt wick, apply a few drops of oil to it. This one was completely dry. If it doesn’t have a wick, apply the oil to the axle where my needle is pointing.

Turn the wheels by hand. Then, using a toothpick, apply one drop of a synthetic 10W-30 oil to anything that spins. Be sure not to miss the bearings where the axles for the wheels go into the motor on both sides. Also catch where the axle for the armature goes through the assembly.

Next, dab a bit of grease onto the end of a toothpick and work some grease onto the gears. Lucas Red n’ Tacky grease is well regarded for its ability to stay in place.

You can also substitute fishing reel oil and grease if that’s more readily available.

After lubing, turn the wheels by hand again. You should find they turn with less resistance now.

Finally, to improve electrical conductivity, apply a drop of Rail-Zip to the axle where it touches the copper pickup.

And that’s all it takes. We have better oils today than we did in 1950, so this type of maintenance doesn’t have to be done very often.

Set up a loop of track on the floor. Put the locomotive on the track and apply just enough power to get it moving. Then let it run for a minimum of 10 minutes both in forward and reverse, if it’s capable of reverse. Try to run it every day for at least 10 minutes for about a week. For some reason, this tends to help.