An SP Class F-125-1 flat car, Part 2

In the first part of this series, a ClassOne Model Works depressed-center flat car was chosen to be modified into an SP Class F-125-1. I showed the addition of steel end decks to one of the “ready to run” models, after removal of the original wood end decks, and drilling of some tie-down holes in the new deck (see that post here: https://modelingthesp.blogspot.com/2024/01/modeling-sp-class-f-125-1-flat-car.html ).

A less visible but important aspect of the ClassOne model is that it has roller-bearing trucks. The SP cars, however, were built with and long retained solid-bearing trucks (there is a photo of the SP Commonwealth truck for this class here: https://modelingthesp.blogspot.com/2023/10/the-new-class-one-flat-car.html ). 

There are various ways to alter roller-bearing trucks to the older type, but the simplest is to just file off the details that make them roller-bearing trucks. You can see that I’ve done this below, in the gray plastic areas.

Next, replacement journal boxes and covers needed to be added in each place that the roller-bearing end caps were located. I sliced these boxes off old plastic truck sideframes that for various reasons had been taken out of service, easy to do with a fresh razor blade. They were then glued onto the round gray areas you see above, using canopy glue. 

This isn’t really quite right, but does provide a non-roller-bearing look. For correct journal-box appearance, these should be a little larger. The prototype Class F journals were 6.5 x 12 inches, substantially bigger than the conventional 50-ton truck with Class D 5.5 x 10-inch journals.

With the work on trucks completed, it was time to paint the car body. I used Tamiya “Fine Surface Primer, Oxide Red” for this. There are those who inveigh against use of “rattle cans” for model painting, but they must not be familiar with the superior spray nozzle of Tamiya products. You do in fact have quite good paint control, and there are none of the “blorts” of paint often produced by cheap rattle cans.

Lettering is a challenge, obviously requiring piecing decal numbers. Here is a builder photo (SP) of one of the two SP cars in Class F-125-1, SP 39900 and 39901, taken outside the Algiers, Louisiana erecting shop where the cars were assembled. (You can click on the image to enlarge it.) Unfortunately, the car has not yet been weighed, thus the light weight and weight limit are not yet stenciled. New date is 3-53.

We can calculate the missing numbers. These were 125-ton cars, thus were equipped with trucks having Class F journals, as noted above. Such journals had a maximum-weight-on-rail capacity of 62,750 pounds per axle. That means that the car’s maximum weight on rail, the sum of the light weight and the load limit, would be 376,500 pounds. There exists a 1959 photo (p. 368 in Volume 3 of my series, Southern Pacific Freight Cars) of one of these cars, after the 1956 renumbering to SP 500501, which shows the load limit as 248,500 pounds. Subtracting the load limit from the maximum weight on rail means that the light weight was 127,500 pounds, which is consistent with what can just be read on a fairly dirty car side.

This is of course the classic example where no commercial decals (that I know of) exist to make lettering easier. For the 7-inch road numbers, I used the nice Microscale set #87-911, which is for wood box cars, but of  course numbers are numbers. The capacity data are more of a challenge, especially duplicating the numbers calculated above. I decided not to duplicate them exactly, but called on a used set I have, originally made for a Pennsylvania heavy-duty flat car. I was able to use other decal sets on hand to find lots of the other small lettering (or good approximations).

Once all decals were applied, I gave the car a coat of Tamiya “Flat Clear,” TS-80 (far better and more consistent than Dullcote, and with a far better spray nozzle than Rust-Oleum Testors seems willing to provide). You can see below that I either matched or simulated the small lettering too.

With the car lettered, and with a built date during my modeling year of 1953, I wanted to add just a light coat of weathering to tone down that “brand new” look. I went to my usual weathering process of applying washes of acrylic tube paints (see my “Reference pages” link at the top right of this post), including a fair amount of “grunge” on the trucks. I then added route cards and a couple of chalk marks.

Even though SP only owned two cars like this, I am happy to have an example, relatively easily converted from the new ClassOne Model Works car. I’m already working on some suitable loads for it.

Tony Thompson