Friday, December 13, 2019

SP 200-ton flat cars, Part 3

In the previous two parts, I showed the Southern Pacific prototype 200-ton flat cars, riding on four trucks under span bolsters (Part 1). I then followed up with a description of the Athearn model of this type of car, including my efforts to make it look better (Part 2). Citation of a link to Part 1 is in Part 2 (which can be found here: ).
     At the end of Part 2, I mentioned that there is a new resin kit from Funaro & Camerlengo, their number 8471, for exactly this type of flat car built from a General Steel Castings (GSC) one-piece frame. I purchased one of those kits, and looked forward to seeing what modern resin casting technology could do with this prototype.
     The body is all one piece, in the spirit of the GSC original, and includes the deck. Here is a view of the body from below. I have already cleaned up some sprue marks and drilled out the truck screw hole.

     Perhaps the most interesting part of this kit is the trucks. The prototype 100-ton trucks had very short wheelbase, shorter even than 50-ton trucks. The F&C truck frames are cast in resin, and look quite good. One might wonder how durable they would be if a model is operated for large numbers of scale miles, but most of us will only run this unusual car occasionally, so I doubt it’s a problem for many. Shown below is the unpainted F&C truck frame, sitting atop a conventional AAR 50-ton truck from Kadee. You can see it is shorter overall, but note where the centers of the journal boxes are located. This shows you the dimension of the wheelbase.

You can also see that the 100-ton sideframe is a deep and heavy design, compared to the 50-ton truck.
     The kit also includes a nicely made and suitably dimensioned span bolster. In Part 2 (link provided in the top paragraph of the present post), I showed the Athearn span bolster I had filed and sanded down to give a reasonable appearance. The F&C span bolster is even thinner, and really looks nice when placed on the trucks as a test. Note you can see the tops of the wheels behind the bolster. The trucks and bolster here are unpainted,and nothing has been assembled yet.

The trucks are shown here with Kadee wheelsets, as recommended in the kit, but in fact these have axles too long for these sideframe castings. They barely roll at all. I substituted Reboxx 1.010-inch wheelsets and they roll nicely in these frames.
     Next came drilling and tapping the various screw holes to put these truck arrangements together. The only interesting part was drilling the hole into the car body for the screw that holds the span bolster. You need to avoid drilling all the way through the body, for cosmetic reasons, and then you need a bottoming tap (or “gun tap”) to thread that blind hole. If you don’t have one of these taps, you can readily buy one on line from any of a number of sources.
     When completed and with 2-56 truck screws inserted, the span bolsters look quite good. Shown below is one of them, now with the Reboxx wheelsets, and all painted with Tamiya ”German Grey” (paint no. XF-63). The top surface isn’t painted as it will be invisible under the car.

Testing these span bolster assemblies showed that they roll freely and swivel nicely into the tightest curves and turnouts. I am pleased with their looks and performance.
     Next in kit assembly are a number of straightforward steps that simply require following the directions, and I won’t go into them. But in a following post, I will take up addition of weight to the car, as well as painting and lettering.
Tony Thompson


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  2. Hi Tony,
    This is fascinating stuff as I love this type of car. A tiny point, if I may, please? Are these really 100 ton trucks? I would have thought that seeing as there are a total of four of them, they are 50 ton trucks, otherwise the whole car would be 400 ton?
    Sorry to be picky (or, dumb?!)

  3. Actually, John, it's not a bad question. But here's how it works. A typical box car might be a 50-ton car, and its trucks are called 50-ton trucks, and of course they carry 50 tons TOGETHER. Likewise for the 100-ton trucks: each PAIR of them carries 100 tons. Thus the span bolster supports a 200-ton car.
    Tony Thompson

  4. Ah, I see! Each PAIR, of course! I get it now, thanks for the explanation!