Wheelsets and Trucks

Compare the trucks of these two box cars. Follow the post for tips on weathering wheelsets and trucks.
Compare the trucks of these two box cars. Follow the post for tips on weathering wheelsets and trucks.

In our freight car building and detailing adventures, we sometimes forget about finishing the wheelsets and trucks that carry the latest builds around our model railroads. Here are a couple of tips to enhance these components and the final freight car effort.


Long ago I standardized on metal wheelsets for all rolling stock. Through many experiences, I found metal wheels seem to reduce the amount of dirt accumulation on the rails and wheels. About a decade ago, I decided to install wheelsets with a thinner tread on most of my freight cars. These thinner treads better reflect the prototype. The wheelsets are often labeled as semi-scale or code 88 wheels. No matter what you use as a standard, the finishing steps will elevate the appearance.

I usually process a couple of wheelset batches, usually 24 at a time, so there are plenty on hand as models are completed. First, I wash these using warm water, a grease cutting dishwashing detergent such as Dawn, and a soft toothbrush. Use a small plastic dish at the kitchen sink and insert a strainer over the drain so stray wheelsets do not disappear. Rinse thoroughly and set aside to dry. Click on any image here to review a larger size.

Wheelsets ready to use.

I use a micro brush to apply a rail brown color on all parts of the wheelset except the tread. I paint the inside axle and backs of the wheels for all the wheelsets first. Once these are dry, I tackle the outer wheel faces. This can be tedious work but you will fall into a groove after the first half dozen. Some people use an airbrush and wheelset holders for this work. Try a few methods and see what works best for you.

I am still working through an old bottle of Polly-S rail brown. Once this is gone I will search for a replacement color along the burnt umber shade. I suspect it may be a few more years before this bottle is done.

Transforming the wheelsets from shiny to weary can make a difference in your rolling stock. Before popping them into the trucks and pressing them into service, read the next part to upgrade your truck appearance.

Trucks ready for service.
Trucks ready for service.

Most freight car trucks are injection molded in a slippery engineering plastic so the wheelsets can roll easily. The predominant color is black although some oxide red or mineral brown trucks can be found. Black trucks look like empty spaces under a model as they absorb light and detail can be difficult to see. I’ve read of modelers using baking soda with a grit blaster to give trucks a rougher surface for paint adhesion. While I’d like to have a grit blaster, I don’t know when I will add that tool to the stable. About a year ago I developed a technique to lighten truck color and to add color.

As a first step, I use a truck tuner to clean and de-burr the axle cones of the truck. The parts are washed in a similar manner as the wheelsets using warm water, a grease cutting dishwashing detergent such as Dawn, and a soft toothbrush. Once they are dry, we can prep for the next phases.

Trucks are clean, taped, and ready to be finished.
Trucks are clean, taped, and ready to be finished.

Using blue painter’s tape, mask over the bearing surfaces. I use small pieces to cover the axle cones and a large piece wrapped around the bolster. Once a truck is taped up, insert a skewer through the kingpin hole. Check the skewer fit before taping up the trucks as some skewers are too large for the kingpin hole. I mount a couple pair of trucks per skewer and usually have three or four skewers ready for finishing.

Paint and powders used to transform the trucks.
Paint and powders used to transform the trucks.

The next step employs a rattle can of clear flat and a product labeled as Rottenstone, which is a very fine polishing abrasive. A Google search will bring up a number of places to purchase the material. I first read about Rottenstone in the Narrow Gauge & Short Line Gazette and bought a container of it at the 1997 narrow gauge national convention. A little goes a long way in weathering many kinds of models. Rottenstone and many weathering powders or chalks act as an abrasive on a working surface. This is why the bearing surfaces are taped over in the previous step.

Hold a skewer of trucks and spray clear flat evenly. While this is wet, dust the Rottenstone onto the truck sideframes using a soft brush. I usually load the brush and tap the material onto the sideframe before brushing. I do this over a container or a sheet of paper so the excess can be collected. Once all the trucks are well dusted, set the skewer aside to dry. The corrugations in a sheet of cardboard are about the right size to hold the skewers.

A few quick steps upgrade these trucks
A few quick steps upgrade these trucks

At this point, you may want to consider adding color to the sideframes. My railroad modeling focuses on late 1926 and many trucks ended up with the same color as the car body, intentionally or just from paint overspray. After the trucks are sprayed and dusted with Rottenstone, the color is a light grey. I add an additional color by carefully rolling a Q-Tip loaded with craft paint across the surface. I don’t want color to get deep into the crevices of the sideframe. By hitting the outer surfaces, the detail is more pronounced and easier to see in service. I usually prep a few trucks using red oxide, mineral brown, and a darker grey so they will look good under freight cars of the typical colors. Here’s another image to compare the truck work. The gondola on the right is an unaltered model.

Weathered on the left and stock trucks on the right.
Weathered on the left and stock trucks on the right.

As a final step, I gently pull an orange color pencil across the springs and I may add a touch of black around the journal boxes to represent an oily area. I have also used rust color Bragdon powders and Pan Pastel colors around the journal boxes. You can go to all sorts of extremes with truck weathering, but I try to just keep it simple. Changing the color from black to dark grey, brown, or oxide red can add to your model.

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15 thoughts on “Wheelsets and Trucks”

  1. Another excellent post – I had never heard of rottenstone, though it sounds familiar. I generally just rattle can spray-bomb the trucks, wheels and all with a dark dark dark almost-back brown then clean the treads with laquer thinner before applying additional dust & rust per the methods you mention. I like the Bragdon powders.

    Question – did any railroads ever paint their trucks oxide red? (or a color that matches the body?) I see some models painted this way and have often wondered about this. I have not found an answer anywhere, but perhaps you know.

    Thanks again for a good read.

    1. Thanks for your comments, Galen! As to your question, I believe some railroads did paint the trucks in the pre-Depression Era. These would have been the same color as the car body (oxide red, box car red, mineral brown) or they were painted with black asphaltum. Of course, some railroads did not paint the trucks and at a point beyond my 1926 focus, the AAR mandated that trucks and couplers not be painted in order to better see any stress fractures that develop. As noted in my post, I do apply color to some of these trucks using a Q-Tip. As there are no color images from the 1920s, I’m guessing on many color applications on the trucks but I do feel there would be more color variety there than seen in the post-WW2 era. – Eric

  2. In the late 1940’s I was walking along the B&O near Takoma Park, Md. and came across a car which I clearly remember. It had been freshly painted – so freshly that the odor of paint hung about the car. Yes, the trucks were freshly painted with the body color.

    For painting wheels I keep them in the frames and use a #1 sable brush held against one wheel while I spin the other wheel. Four spins and then an axle rotation and one wheelset is done. With practice I rarely get any paint on the treads, and that comes off with a toothpick before it cures.

    Lately I’ve tried adding a bit of rust color on the springs – a little goes a long way. A touch of oily black under each solid bearing cap is barely noticable.

    1. Thanks for sharing your experiences, Dick. That’s a nice wheel painting tip, too! – Eric

  3. Thank you Eric and Dick for the replies. I had heard that the Chinese paint their steam locomotive drivers and wheel faces red in order to better spot cracks, so I had wondered also if painted trucks served a similar purpose. In an era of cast steel trucks that might make some sense, beyond just a cosmetic reason.

    So the next question – is there a database anywhere that lists what railroads did this, or which cars’ trucks were painted this way? I imagine manufacturers like Westerfield or Sunshine might keep such information on a car by car basis as part of the research that goes into producing such accurate and detailed kits, but it would be nice to have a master list somewhere that could be updated, like a Wiki or spreadsheet. Could this be a project for the members of the Steam Era Freight Cars list?

    1. Galen, there is no database to track what railroad painted trucks on their cars. This may also change from batch to batch, or when car was rebuilt, or even the specific car shop where heavy maintenance work was done. Instructions in Westerfield kits note paint color and application for most of their models. I’m working on a couple of this now where the directions note the car was painted with box car red paint on all surfaces, which insinuates the trucks and couplers were also painted. Trucks pick up the dirt and grime before much weathering is seen on the rest of the car, so a painted truck my lose most of the color quickly. I would recommend prepping a range of painted and weathered trucks to match models that come out of your paint shop and weathering factory. Try to randomize the mix of red, brown, and black trucks among your box car fleet. I think just having truck color variation on several of your box cars will offer a slightly different look to your model fleet. – Eric

  4. The video “Pennsylvania Glory volume 3” 1930’s, 1940’s, 1950’s has many examples of freight car trucks painted “Boxcar Red”, “Oxide Red”, and “Freight Car Color” (Pennsy’s name). My VCR copy shows a copyright of 1991. Herron rail services 2016 n. village ave. tampa, fl 33612. I’m sure it’s available on DVD now.www.herronrail.com

    1. Armand, I bought a 6 ounce jar at the 1997 National Narrow Gauge convention from Coronado Scale Models of Phoenix. The Narrow Gauge & Short Line Gazette ran some weathering articles back in the 1990s that used Rottenstone. I’ve used about half of the container in about 20 years. Rottenstone is used as a finishing rouge in the furniture industry, so you might find some at a woodworking store. I’ve been using PanPastels more lately and achieving a good finish on the trucks. Experiment and report back! – Eric

  5. Eric,

    Some good tips there. I’d like to add the following; If the trucks have cast-on brake shoes, be sure to paint them a bright rust color with a micro brush of colored pencil. This really adds a depth to the sideframes. The shoes were frequently changed and never painted, so their color usually contrasted with the other truck parts.

    The photo of your truck-ka-bob made me chuckle!

    1. Thanks for the tips, Jim! I’ll be sure to keep the truck-ka-bobs away from the grille. – Eric

    1. Jim, I’ve been using Intermountain code 88, semi-scale wheel sets for most of the freight car fleet. – Eric

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