Friday, May 29, 2015

Another approach to tank car platforms

Platforms around tank car domes (or valve bonnets, on high-pressure or ICC-105 cars) have been a challenge to modelers for some years. The most familiar models, such as the Athearn blue-box “chemical” tank car, have a poorly rendered attempt to look like steel grid, not only far too thick but also not “see-through.” Until 1948, when “other than wood” walks became mandatory for tank cars, such platforms were commonly wood, not steel grid, so older tank cars may well not have the steel grid in any event.
     Before continuing, I should also repeat what I have often said, both in this blog and in many clinics, that the Athearn “chemical” tank car has a grossly oversize valve bonnet and platform — they are about S scale, not HO scale. The valve bonnet can be replaced, with the correctly sized Precision Scale brass part, number 31005 (I have shown that replacement earlier, at this link: ), or with other replacements, such as Frank Hodina’s resin bonnet (see this post: ).
     The platform, however, is the subject of the present post. About a year ago, I posted a description of my (not very successful) effort to kitbash the Athearn platform into a smaller wood-planked version, with shorter posts, which is at: . By “not very successful,” I mean that the platform still had pretty big posts, and was a real pain to cut up and reassemble. You can see it on the foreground Dow car in this photo (the photo is repeated from that previous post). Behind it is a stock Athearn car with its huge bonnet.

The modified platform posts on the Dow car are about two-thirds the height they originally were, but are still a little too tall, and are still way too thick. And although the platform is about the right length (parallel to the rail), it is too wide. There has to be a better way.
     I decided to try something entirely different with the Hooker car that is in the background of the photo above. First, I discarded the Athearn platform entirely. I learned my lesson by trying to rebuild the one on the Dow car. I then used a razor saw to slice off the Athearn valve bonnet, and filed the cut surface to match the tank. This leaves some odd ribs and round depressions on the tank top, which need to be cleaned up. I shaved off the offending parts (note the thin black stripes right at the edge of the orange areas below — you can click to enlarge the image), and filled the two depressions with Squadron Green putty.

     I intended to keep the wide black stripe on the body, but needed to match the body color for the areas I had repaired. Eyeballing the color, I tried a mix of 2/3 Daylight Red and 1/3 Caboose Red (old Floquil). This matched fairly well, though the mix is perhaps a trifle too red; straight Daylight Red might have been better. But since the car will receive some weathering along its top surface, this isn’t serious.

     I now assembled the two parts of a Hodina valve bonnet and attached it to the tank with canopy glue. This bonnet is barely half the diameter of the Athearn molding. I show it unpainted for clarity, but it will be black along with the body stripe, as was Hooker practice (the original Athearn bonnet, with its orange sides, does not match any Hooker photo I have seen).

     Now for a platform. I decided to try the platform parts for the Atlas kaolin tank car, which are sold separately. This is their part  number 9170013, and is called an “upper platform with handrail.” At first glance, it is the wrong shape for the tank car I am looking at, though delicately molded and with see-through grid areas:

But since these are inexpensive platforms, one can use more than one to achieve the desired platform. I cut two of them, so as to use the “short end” of each, the left end in the photo above, thus creating the typical platform for a 1948 tank car. (That’s the built date on my model.) These platforms have mounting pegs molded to them, so I drilled no. 64 holes to accommodate them on the car, and used canopy glue to attach the two halves.

Compare the photo at the top of this post, for the difference in platforms. This platform is smaller than the black stripe, while the Athearn platform extended beyond it.
     Still, there may be some modelers who would say, “Well. c’mon, it still has about the same platform.” For a comparison, here are the Atlas part on the left (of which I used less than half) and the original Athearn platform on the right. Draw your own conclusions.

     This tank car now looks much better. What about the tank size? The Athearn “chemical” car is around 11,000 gallons size, which is all right for chlorine service, to which many Hooker cars were assigned, so the car size and lettering are all right in this case. This project was simple and yielded an improved Hooker tank car, and I’m happy with the result.
Tony Thompson


  1. The bonnet and platform, on the same sprue, is an excellent candidate for 3D printing.

  2. I would agree, especially for a wood-planked platform. I would assume the handrails would need to be wire.
    Tony Thompson

  3. I'm late to the ballgame on this one, but I have several of these I'd like to convert. Is the Hodina valve bonnet still available? It's probably scratch-able but I thought I'd ask. I found an Atlas car at the local hobby shop which is useful as a reference point.

  4. You could contact Frank and ask, though this is a pretty old part. (If you don't have his contact, let me know and I will supply privately.) The Precision Scale brass version is very nice too, and I use both. And as you say, it would not be hard to scratchbuild a credible version.
    Tony Thompson