Reworking an Athearn “Blue Box” tank car

I have written numerous times in this blog about the uses I have found for Athearn’s old “Blue Box” (40-foot) tank car, whether the conventional car or the insulated car (called a “chemical car” by Athearn). I won’t go into all the background here, but will just give one example of previous work: https://modelingthesp.blogspot.com/2011/05/modeling-sp-tank-cars.html .

I have in mind a conversion of the insulated version of this car, to create a credible high-pressure tank car. I rummaged around in my various stashes of tank car kits and parts and left-over pieces, and soon found one of the insulated bodies, but no other parts from a former kit. No problem. Years ago, I purchased multiples of nearly all the parts for this kit, directly from Athearn (see this post: https://modelingthesp.blogspot.com/2015/12/athearn-tank-car-parts.html ).

The goal is one of the Shell Chemical high-pressure cars, for which decal set D245 has just become available from National Scale Car (here’s a link: https://nationalscalecar.com/product/d245-shell-tank-cars/ ). These are for a car in series SCMX 2001–2147, which were General American Transportation Co. (GATC) ICC 105A-300W insulated and pressurized tank cars of nominal capacity of 11,000 gallons for transportation of anhydrous ammonia. This is close to the size of the Athearn insulated tank body, and its underframe, though crude, is intended to represent a General American frame.

So I could quickly put together what are the basics: the insulated body, one of Athearn’s bottom sheets, the two-part underframe, and most important, a package of Precision Scale parts 31005: correct-size brass valve bonnets for high-pressure cars (for more on valve bonnets, you can visit this: http://modelingthesp.blogspot.com/2010/12/upgrading-old-models-2.html ).

The first step is to remove the immense Athearn attempt at representing a valve bonnet (oversize even for S scale), filing the area smooth, and fitting a Precision Scale bonnet in its place. For joining dissimilar materials like these, I have found canopy glue to be the best choice, making a good bond regardless of the two materials, and being quite tenacious when set.

The next step is to remove all the rivet detail from the bottom sheet, correctly placed for a three-compartment car but obviously extraneous for an insulated car, with its smooth outer jacket. I simply filed and sanded the rivets away. Incidentally, many tank car owners chose to make the bottom sheet black, along with the underframe, while applying various colors to the top part of the tank. Such a paint scheme is quite easy with the Athearn design, as the two parts are separate.

Here are both these parts, as modified, and the Athearn weight, which from experience I know to be about right for these cars, and which I will use.

There is an additional modification which, though minor, does need to be made. The Athearn underframe, as mentioned, was designed for their three-compartment tank car, and as such, has representations of three outlet or drain pipes in the underframe. Naturally the outer ones would be removed for a single-compartment car, and all should be removed for a pressure car, which cannot be unloaded from a bottom outlet. The photo below shows, at left, that center outlet and at right, one of the three-compartment outlets. These are simply snipped off.

With these parts of the project completed, I can go ahead and paint the tank body parts a light gray color. Safety appliances such as grab irons, ladders, and dome platform were usually black on cars like this, so I can install and paint them separately. But I will cover those steps, along with assembly and lettering, in a future post.

Tony Thompson