Wednesday, December 5, 2018

Upgrading the Roco “Army” flat car

Long familiar on the outskirts of prototype modeling in HO scale has been the flat car produced by Roco in Austria and marketed in the United States by AHM (Associated Hobby Manufacturers). This flat car was usually sold with Buckeye 6-wheel trucks, and was usually painted black, though it has been produced in Army olive drab and even in a camouflage scheme. It was ordinarily sold with two vehicles on it, from half-tracks and 6 x 6 trucks, to bulldozers, front-end loaders, and even Sherman tanks. Here’s an example.

     Does this represent a real car? It is lettered as a 100-ton capacity car, though it looks much like any garden-variety 70-ton flat car of 53- or 54-foot length. As it turns out, the usual car number on the Roco models, USAX 38065, does indeed fall within a 650-car group of U.S. Army flat cars of 100-ton capacity and 54-foot length. I remember Richard Hendrickson once saying that this model could be upgraded to be usable in a prototype context.
     I have had a second-hand example of this model buried in the “some day” stash for years, and it might have remained there, except while digging for something else, I came across it. I don’t think it ever had vehicles on it when I owned it, and did have large blobs of Walthers Goo or equivalent all up and down the deck, doubtless indicating the location of loads applied by a previous owner.
     I decided to see if the old glue would come off, and indeed it scraped off nicely, with an X-acto chisel blade. But you can see the glue “scars” in the photo below. (These scars not only don’t matter, they can even be seen as a plus, since decks on cars like this take quite a beating in service, and these scars are a good start on modeling that service damage — more on that later.)

Note also the four large rectangular openings in the deck, probably the place where some kind of load attachment frame was inserted, as can be noted for several different loads sold on these flat cars. (You can click the photo above to enlarge.) These will have to be filled, or the deck replaced.
     Experimentation showed that the rectangular deck holes are very close to HO scale 6 x 10-inch styrene strip (Evergreen no. 8610), so I cut four short pieces of that strip that would sit flush with the deck, and glued them in with styrene cement. Roco flat cars which originally had other kinds of load attachment frames might call for other sizes of filler material.

     The Roco Buckeye trucks are not bad looking, though undersize, but have really poor wheels, about 30 scale inches in diameter and with “pizza cutter” flanges, as they are sometimes called. Whether the prototype had smaller-diameter wheels for clearance purposes, I don’t know for sure, but the deck height of the cars is shown in the Equipment Register as 4 feet, 2 inches. As a comparison, the postwar flat cars bought by SP from AC&F had a deck height of 3 feet, 10 inches, and those cars had 33-inch wheels.
     Accordingly, I don’t think these USAX cars had undersize wheels. But as stated, the flanges alone rule out the use of these Roco wheels. The Roco wheelsets can be replaced, of course, but I thought I would search for better trucks. I went through a couple of prospects for replacement, and will return to that topic in a following post.
     The molded-on grab irons on this model could easily be replaced, but on a black flat car are far from obvious. The rather thick sill steps are another matter, and really should be corrected. An example of the original step shape is shown below (a photo taken before correcting the deck).

I sliced off these heavy steps and replaced them with A-Line metal sill steps, using my usual method of first placing a styrene block behind the side sill so that drilling into the sill is supported.

     The main reason I wanted to upgrade this car to layout standards is that I have some military loads, and these certainly did move on SP’s Coast Route, with the abundance of military bases in California in the early 1950s. I will come back to loads for this car in a future post, along with completion of work on the car itself.
Tony Thompson


  1. Mt. Vernon Shops makes the right decals for these cars.

  2. Thank you, Richard. I had been told this earlier, but had not yet ordered a set, so your comment was helpful in motivating me to go ahead and get one! Thanks again.
    Tony Thompson