How to disassemble a Marx 999 locomotive

Last Updated on November 19, 2018 by Dave Farquhar

Disassembling a Marx 999 locomotive isn’t too difficult, and it’s easier than the Marx 666, but it helps to have some instructions.

The nice thing about the 999 is that if you can disassemble it, there’s a long, long list of Marx locomotives that disassemble in pretty much the same way: the Commodore Vanderbilt, the Mercury, the tin Canadian Pacific 391, and the tin steamers 592, 593, 594, 833, 897, 898, and 994.

Marx designed its trains so that a father or older brother could service them, so it comes apart with simple household tools, and you can get most of what you’ll need to service it at the nearest hardware store, with the probable exception of the bulb for the headlight.

What you’ll need

Projects like this always go more quickly when you have what you need in advance.

Get replacement screws that match the screws already on your locomotive. Marx usually would have used slotted screws, but I find Phillips screws on them from time to time. If you’re concerned about ease of maintenance, Phillips screws are easier to work with.

Dropping out the Marx 999 motor

You need to drop out the motor to do much of anything. Remove the two screws on either side of the motor. Do not disturb the exposed screw on the motor itself. It doesn’t need to be removed for disassembly, and if you lose it, the motor won’t run without it.

Marx 999 ready for disassembly
The screws in front of the side rods have been removed and this Marx 999 is ready to take apart. Note the screw in between the two large wheels. Leave that one alone.

One of the most common reasons for Marx motors not running is because that screw is missing, so if yours won’t run and that screw is missing, you may be able to just stop here, replace that screw, put the locomotive back together, and have a running train again. Sometimes that screw is a 6-32 machine screw and sometimes it’s a 4-40 machine screw. To figure out which one you have, try one of the screws from the side of the locomotive. Don’t force it in. If it threads in easily, you need a 6-32. If it gives resistance, you need a 4-40. Any well-stocked hardware store will have both kinds; get the shortest screw they have. A quarter-inch screw is plenty.

Tilt the motor assembly down, then alternate pulling it down and forward until it releases.

Service the motor as needed. I have some advice on cleaning and lubricating Marx motors here if you need it. I do recommend testing the motor before reassembling the locomotive, but the 999 and similar locomotives aren’t too hard to take back apart if needed.


Let’s talk lubricants for a minute. Lucas Red n’ Tacky grease works splendidly and is available near you. While you’re there, pick up a quart of synthetic 10W-30. Apply grease to the gears with a toothpick, then apply a drop of oil to the wheels where the axles meet the bearings with another toothpick. Use the leftover oil in your lawnmower come spring.


Something else you’ll want to do while you have the motor out is to clean the driver wheels. They are always filthy, even if they look clean, and will run much better after a cleaning. A cotton swab with some mineral spirits is the cheapest way to clean the gunk off them. Mineral spirits, if you’re not familiar with it, is a cheap and effective solvent sold in hardware and home-improvement stores in the paint aisle. It’s normally sold as a paint thinner.

It would also be a good idea to blow the motor out with some compressed air. You can get by without this step, but it can loosen some of the debris that’s accumulated through the ages and make it easier to get it clean.

Replacement parts

If you lose one or both of the screws holding the motor in, they are 6-32 machine screws, 3/8 inch in length. Replacements are available at any well-stocked hardware store. A slightly longer screw should be OK to use if they don’t have 3/8 inch in stock.

Removing the remaining parts

Generally speaking, you’ll only want to remove the bell and handrails if you are repainting the locomotive. Chances are you can only do it once or twice before metal fatigue sets in and you break your tabs.

Removing the handrails

The tabs for the bell are in the center of the locomotive toward the left. The other four sets of tabs are from the cotter pins that hold the siderail. The brass bolt holding on the truck is to the right.
The tabs for the bell are in the center of the locomotive toward the left. The other four sets of tabs are from the cotter pins that hold the siderail. The brass bolt holding on the truck is to the right.

The easiest way to remove the handrails is to straighten them from the front of the locomotive, then bend the four cotter pins inside the locomotive to release the cotter pins, then push the handrails out. If they are dirty, you can clean them with almost any metal polish. If they won’t stay shiny, a cheap alternative to replating them is to paint them with silver-colored spray paint.

After polishing or painting them, if you want them to stay clean and shiny, spray them with a clearcoat spray afterward.

Removing the bell

The bell is held in place by two tabs at the top of the locomotive. Straighten both tabs to get it to release, but only straighten them as much as is necessary to free the bell, to avoid breaking the tabs. I’ll show you a nifty trick at reassembly time to help avoid breaking tabs.

Removing the rear truck

The rear truck is held in place with a hex-headed brass bolt. Remove the bolt to remove the truck.

If you’re disassembling the locomotive in order to repaint it, be sure to let everything dry thoroughly at least overnight before reassembling it. Here are some more tips on repainting a 999.

Replacing the Marx 999 headlight

The light bulb screws in to the front of the assembly, in front of the reverse unit.
The light bulb screws in to the front of the assembly, in front of the reverse unit.

The bulb is a standard 14-volt 1449 type commonly used by Lionel, sold by Trainz. It screws into the front of the motor assembly.

A 14-volt bulb is a bit under spec though. A Marx transformer can output up to 15 volts, which will burn out a 14-volt bulb prematurely. An 18-volt 1447 will also work and will last longer. It will just burn a bit more dimly, but the increased life expectancy is worth it. Since changing the bulb is a bit of a pain, I would replace it with a 1447, ideally an LED version. Either type will likely last a lifetime, but the LED bulb will reduce the load on your transformer by a good two watts, so it’s an upgrade worth doing. You might want to buy several and upgrade your whole fleet, or at least your most commonly used locomotives.

Replacing the bell and handrails

Press the bell into place through the hole in the top of the locomotive. To avoid the risk of breaking tabs, instead of bending them back, slip a short length of heat-shrink tubing over each tab, pull the bell and tubing tight against the locomotive body, then direct a hair dryer at it. The tubing will hold the bell in place, and if you ever need to remove the bell again, you can just cut the tubing off with a utility knife, rather than risking metal fatigue.

Start the handrails from the cab of the locomotive, hooking the ends in through the cab, then push the cotter pins into the holes in the boiler and push the front of the handrail into the holes in the cowcatcher.

You can do the same trick with heat shrink tubing to hold the handrails in place.

If you removed the truck, it simply screws back into place with the hex-headed brass bolt. Don’t overtighten the bolt, or you run the danger of damaging the post.

Replacing the Marx 999 motor

Marx 999 reassembly
When reassembling, tilt the headlight end in first, as shown, then slide the assembly back to engage the grooves.

Putting the motor back in is harder than getting it out in the first place. Counter-intuitively, it’s easier to tilt the headlight end in first, then you’ll have enough clearance that you can get the grooves in the motor assembly engaged with the back of the locomotive.

It takes a bit of trial and error to get everything to line up as the inside of the locomotive is a bit cramped. Work the motor assembly forward and backward until it fits properly.

You can tell the whole assembly is lined up when the screw holes in the front are all lined up and the motor doesn’t fall out the back. Replace the two screws that hold the motor in place.

Removing and Replacing the pickup shoe

If you need to remove the pickup shoe to replace it, it pries off fairly easily with a slotted screwdriver. Hold the shoe in the upward position and pry on one side, where the hole in the shoe slides into the motor’s base plate. Just pry slightly and the shoe will pop out fairly easily. Be careful not to lose the spring that sits under the pickup.

There’s a wire soldered onto the shoe, so if you replace the shoe, you’ll need to desolder the wire and solder it to the replacement.

To replace the shoe, slide one side onto the notch in the pickup plate, then tilt it down to the other end. If it doesn’t clear the notch, spread the pickup slightly with either a pair of needlenose pliers or a slotted screwdriver until it clears the tab, then drop it into place.

Overview and history of the Marx 999

I put this at the end since you probably already have one if you’re reading this, but if you’re in the market for an O27 locomotive, this one has a lot to offer.

The Marx 999 was Marx’s first diecast 2-4-2 locomotive, similar to Lionel’s Scout locomotives, intended to be scaled at 1:64 to compete with American Flyer’s fledgling 1:64 line that was introduced in 1939. The first 999s produced in 1991 had a slotted cowcatcher with open spokes that was fragile; these early models are more valuable than the rest. Later models had grooves molded into the cowcatcher, produced in 1941, 42, and 46, but that still proved too breakable. Marx redesigned it with a solid front that proved much more durable. This variant was produced for a good number of years. Production stopped during World War II but resumed after the war.

Downside to the Marx 999

The Marx 999 does have the fat-wheel issue that makes it unable to traverse Lionel switches. A few of the later models ended up with the later double-reduction motors, but they are difficult to find. Legitimate double-reduction 999s have the Marx logo on the cab, rather than on the boiler. Once the 999 had run its course in the United States, Marx shipped the molds to Plastimarx, its subsidiary in Mexico. Early Mexican-produced 999s had the double reduction motor and some even retained the “Made in U.S.A.” stamp, though the original Marx logo was always blanked out on Plastimarx 999 production. Later Plastimarx 999s were made with plastic bodies. These have collector interest as plastic 999s were never sold in the United States, but they do not run as well as earlier metal 999s.

Advantages of the Marx 999

The design and proportions of the 999 mean it goes well with virtually any train Marx produced. It doesn’t dwarf the 6-inch tin cars, it was designed for the 3/16 tin cars, and the size goes well with the 4-wheel plastic cars. The 8-wheel deluxe plastic cars are the only challenge, but as long as you don’t put a boxcar first in your consist, it looks good with those too.

The 999 is a good all-around locomotive and the common variants typically sell for $20-$35 in good running condition. The rare variants are rare enough to keep collectors hunting for a good while.

Parting thoughts

If this is the first time you’ve tried to fix a train, the Marx 999 is an excellent choice because it comes apart and goes back together very easily.

I didn’t learn how to fix trains until I was well into adulthood. When I was a kid, I didn’t have anyone around who had much in the way of mechanical ability to learn from. I started picking this up when I unboxed the trains that had belonged to my dad growing up and some of his stuff didn’t work. I share what I’ve learned (and, let’s face it, what I’m still learning) in hopes of other people being able to use it to do the same thing.

You’ll find it’s well worth the effort. Marx trains are very dependable, and I find it relaxing to watch a train pull its consist around a layout at the end of a long day.

I hope you’ve found this post helpful. If you have, please share a link, whether it’s on your own blog, a forum, a discussion group, Twitter, or Facebook. Thank you!

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