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: http://modelingthesp.blogspot.com/2011/05/modeling-sp-tank-cars.html.
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 www.smallparts.com – 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.