How To Restoration & Repair Repair Marx plastic rolling stock

Repair Marx plastic rolling stock

By Mike Small | March 17, 2025

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Although our family had a wind-up Marx set when I was very young, my real interest in Marx trains began when I received a Marx Allstate set for Christmas about 1961 when I was 10. My father bought it at the Sears surplus store on North Main St. in High Point, N.C. for, I think, $10.00.  It was quite simple with a 490 steam engine and 4-wheel plastic cars, but to my amazement it included 12  telephone poles, 12 signs, and 3 non-powered signals. 

I already had a low-end Lionel set, so now I could begin to compare manufacturing and molding differences of the two companies. I’ve always liked to study the details of plastic bodies and this would eventually lead to repairing them. Although Marx trains are generally not as realistic as Lionel; they are quite interesting and collectible. I’ve also found their motors to be very reliable. 

For many years I focused on Lionel, Kusan, O scale, and even N gauge. Over time, I realized I had overlooked learning about the trains produced by Louis Marx & Company. They manufactured three categories of tinplate cars and three of the plastic ones. I particularly like plastic, so I’m going to talk about repairs that I’ve done on some of these cars.

Types of Marx plastic cars

three plastic model pieces of rolling stock
Three Marx hopper repairs and modifications. The missing plastic areas were filled with styrene pieces. The black hopper now has a plate with a pin for the truck under each end. The gray hopper has a roof fabricated from styrene (Marx made no covered hoppers in 0-27). Mike Small photo

The three types of Marx plastic cars are four-wheel or lightweight (as some call them), eight-wheel, and what are often called “deluxe.” The four-wheel and eight-wheel cars are the smaller ones and are from the same molds. 

On the four-wheel versions there is the addition of molded on simulated truck sides, and some include molded on coupler support bars. Deluxe cars are the larger, more elaborate cars that have additions like sliding doors or metal ladders and handrails, as on the tank cars.

The four-wheel cars are the most likely to be broken since they came from inexpensive sets that children played with. The truck sides and coupler support bars are the most-often broken sections. In the Fall 2024 issue of CTT (Tips & Tricks), I outlined how I’ve made repairs to these. 

I sometimes paint and decal cars and have hand-lettered some. If a car is in original condition I try to avoid painting it, but if there’s plastic missing and I have to make a repair then I don’t worry so much about changing it to another scheme, unless it’s a rare item.

Painting and decaling plastic cars

four pieces of Marx rolling stock
The author painted and decaled these four Marx freight cars. He added the plastic roof to the covered hopper. Decals are S scale by K4 Decals (Marx 027 cars are close to S scale size). Mike Small photo

I recently painted and decaled four cars. I had three of these planned for a long time and looking for decals. A friend introduced me to K4 Decals and they had what I needed in the appropriate size. (Since Marx 027 is close to S scale size I went with these.) 

I started with the two hoppers. The hoppers tend to have broken framework on the ends. I keep sheet styrene or polystyrene on hand such as that made by Evergreen Scale Models. Sizes such as .040” .060”, and .080” are useful for repairs.  I’ve replaced quite a few beams and grab rails on these hoppers using this material. One hopper had nearly everything missing or removed out of the ends so I fabricated all new parts. I removed the molded-on truck sides and added .080” styrene plates on the bottom with pins to fit into trucks.

model covered hopper car
This car began life as a Lehigh Valley black coal hopper. Repairs were made to the car then a roof was fabricated from sheet styrene or similar plastic. The roof walk is sheet, with scribed lines using a hobby knife. The round roof hatches were cut out as round as possible, then filed the rest of the way. Decals are S scale size from K4 Decals. Mike Small photo

For one hopper I fabricated a roof from styrene (I came up with this idea. Marx did not make any covered hoppers). For the round roof hatches, I hand cut pieces as round as possible, then filed them the rest of the way.

On some of the last four-wheel plastic cars that Marx made, the truck sides were painted black. On one of my rebuilds I did black sides and on another reddish-brown.  

red model caboose with repair
Repair on Marx caboose body. Mike cut a piece out of another damaged caboose, but had to cut behind the end, which got a little tricky. The finished product was painted and decaled for the Atlantic Coast Line. Decals are S scale by K4 Decals. Mike Small photo

My fourth car, a caboose, had a piece broken off of one corner of the roof. This was a tricky fix, but I cut a piece out of another junk caboose to repair the damage.

I like the simplicity of using spray paint, but color choices can be limited. I’ve been using formulas that are a paint and primer in one, following the instructions on the can.

Note: Use a paint booth or spray outdoors and be sure to have adequate ventilation. I do mine outside (but not if it’s too wet or windy). 

orange model caboose
This Marx eight-wheel caboose was repaired, painted, and decaled. Decals are S scale size by K4 Decals. The car was formerly Southern Pacific red. Mike Small photo

I have not had a problem with a paint and primer formula attacking plastic, but you may want to test first in an inconspicuous place or on a scrap. In the past I’ve had paint (without primer) attack plastic, but if I used a coat of primer first, had good results. I generally prefer satin finish paint.

Instructions usually state to wait 48 hours between coats. I might have to do three coats to cover things well, and this will add up to a span of several days to complete the job.

silver and black boxcar
A Marx eight-wheel plastic boxcar that has been repaired, painted and hand lettered. When adding hand lettering, Mike applied paint with a fairly sharp pencil tip, then let it dry. He then used a hobby knife to scratch around the letters to shape them up. Mike Small photo

I collect and operate a mix of Lionel and Marx equipment. I try to give the Marx cars somewhat equal time with the others. Mixing things up in train operation can bring a lot of enjoyment!   

Supply list

Sheet styrene, such as Evergreen Scale Models .040”, .060”, and .080”

Utility knife (or hobby knife)

Sanding stick or small files

Testor’s Cement for Plastic Models

Testor’s Contour Putty

3/4” masking tape

 Spray paint + primer (or separate primer and paint) 

Tweezers

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