Saturday, June 4, 2011

Modeling SP tank cars, Part 2: handrails

There is an important omission in my post about modeling SP tank cars, namely how handrails are modeled in light of the changes in the tank arrangements. (This was brought to my attention in a detailed email from a reader of the blog, to whom my thanks are due.) My original post can be viewed at:
     There are several issues involved in the tank handrail. First, as I mentioned in the original post, one can either use the Athearn handrail supports which are cast on the tank (less visible on a black tank car) or substitute the fine brass ones from Precision Scale. This in turn suggests a second issue: what diameter should this handrail be? Prototype handrails were 1.25-inch (nominal) iron pipe, which, as any table of nominal pipe sizes will tell you, has an outside diameter of 1.66 inches. This corresponds almost exactly to 0.019 inches in HO scale, and brass wire of that diameter is available from Detail Associates. The Athearn handrail wire is thicker, close to 0.026 inches. If you replace the Athearn handrails with smaller brass wire, no problem, but some modelers do like to use the Athearn wire. I’ll touch on how to do that below.
     The Precision Scale handrail stanchions, their part no. 32110, are probably intended for 0.015-inch wire but can be carefully drilled out to 0.020 inches to accommodate 0.019-inch handrails, which is what I’ve done on several tank cars. Use of these stanchions also permits reducing the number of handrail stanchions on the tank to that of the prototype (see for example the builder photo of SP Class O-50-13 in my previous post). If you go this route, the Athearn handrails can be used as a template to bend a new 0.019-inch brass wire handrail to go all the way around the tank, in other words a one-piece handrail instead of Athearn’s two-piece design.
     For those who want to use the Athearn handrail, the problem comes with the fact that the original tank body is set up for a ladder on each side, but the SP cars only have a ladder on one side, so the Athearn handrails obviously can’t just be attached as originally intended. The iron wire used by Athearn is evidently cold-formed and is very brittle, much too brittle to straighten at room temperature. But if you have a gas stove, you can heat the ladder-end bend in the Athearn wire until it’s at orange heat, then immediately use pliers to straighten it (if you are even a little late, it cools enough to return to brittleness). It’s worth practicing on some scrap wire, if you’re going to try this. As you can tell, I have tried it and have made it work, but you have to straighten it when it’s really hot.
     So if you do this, instead of the two U-shaped wires provided by Athearn with bends at each end to drop into the ladder-top holes on each side, you have instead two U-shaped wires with only one bend (if you want to preserve the Athearn ladder attachment) or no bends at the ends. Now you have to cut them to fit, and join them. The joining problem, of course, exists also if you bend a new handrail from brass wire.
     I use a solution to this problem which is apparently an old one, but I learned it from Ted Culotta in his “Essential Freight Cars” series in Railroad Model Craftsman. It involves a piece of hypodermic tubing which will just slip over the ends of the wire handrail. The key is that this tubing has very thin walls. Here’s a clear photo of how it looks when it’s installed (obviously unpainted), from one of Ted’s articles.

     The small length of stainless steel tubing is just to the right of the Precision Scale handrail stanchion. For the 0.019-inch brass wire, you can use 0.020-inch inside diameter hypodermic tubing (available from Small Parts at – the smallest quantity is 12-inch lengths, and if that’s not more than a lifetime supply for this purpose, you are indeed a serious tank car modeler). If you‘re using the thicker Athearn wire, you want tubing to fit, namely the 0.029-inch inside diameter tubing. A small drop of CA glue will hold this tubing in place.
     This approach to the problem of closing one or more joints in a tank car handrail is elegant and all but invisible when completed; and to the extent that it is visible, it looks something like the prototype pipe union actually used for this purpose.
Tony Thompson


  1. Hi Tony,

    Your article on SP tank cars is perfect and answers so many of my questions. I already had your original Trainlines article and the update is most welcomed. One question: if the dome on Athearn tank cars is too short for SP prototypes, is this true for other reporting marks as well?

    I will be using the decals for SP tank cars that were currently offered by Gerald Glow.

    I also plan on following your suggestions about redoing the hand rails. I've located the stanchions and stainless tubing but I'm not sure of the .019" brass wire. It appears that Walthers carries Detail Associates brass wire (P# 229-2506) but the description is a bit confusing and they couldn't tell me the length of each piece. I do have a call into DA and with luck, they can verify this to be the right one unless you can, first.

    Again, this is great info on tank cars. Now, if you could add to your blog on SP gondolas with the same type of info including new decals by Jerry?

    Thanks so much,
    George Corral
    La Grange, KY

  2. George, that's the right DA part number for the 0.019-inch wire. You get six pieces, each 12 inches long.

    About the dome size: yes, it's wrong. The rule in those days was that the dome had to contain a minimum of 2 percent of the tank volume to permit expansion. The Athearn dome is just about 2 percent of a 4000-gallon compartment (appropriate for the three-compartment car), which is why I said the domes would be right for such a car, but obviously well undersize for a single compartment of 12,500 gallons. It makes the Athearn single-dome model just plain wrong for anything, which is too bad.

    I will think about the gondola project. I take it you want to do GS gondolas, not GB? Or would you want a more general set which could do all kinds? I haven't asked Jerry yet about doing it, but he can (within limits) print decals on demand, so it might work.
    Tony Thompson

  3. Gotcha about the dome size. I've got about 12 tanks to do this way.

    I currently own one F&C "War Emergency" GB gondola, four Detail Associates GS (G-50-22 & G-50-23) with no decals, and two Ulrich GS (G-50-9/12) gondolas with poor markings so I really need decals for GS gondolas but I'll take anything because I'm going no where fast at this point.

    Help with decals would be most appreciated as would any "corrections" article about gondolas would also be very much appreciated.

    Thanks again, Tony, for all the great info.

    George Corral

  4. There would be less to say about gondola modeling, but I could summarize what I know. I provided the great bulk of the information used by Rich Meyer to make the Champ "Super Set" SHS-144 for SP gondolas, primarily GS classes. I could re-assemble that information and create decal artwork.

    I agree with you about the great majority of the Ulrich model markings; they are often pretty bad, though it does vary from model to model. Perhaps I will put together a post about what I've done with some of these problems,
    Tony Thompson

  5. I agree, the markings on my Ulrich cars look as if they were made with a sponge.

    I look for the Champs SHS-144 decals online everyday but so far no luck. It would be great if you could resurrect that decal set.

    I reiterate that any and all help in modeling the SP would be greatly appreciated and I await anything you provide with bated breath.

    Thanks a bunch, Tony.

    George Corral