Wednesday, June 28, 2023

Building a Dry Creek ballast car

In an earlier post (at: ) I described the new “Hart convertible” ballast cars being offered in kit form by Dry Creek Models and its proprietor, Robert Bowdidge. The car bodies and parts were 3-D printed with a Form One Plus printer, about which you can learn more at the Dry Creek website (see it at: ).

I recently discovered, looking at old posts, that I never completed my description of actually building one of these cars. In this post, I will briefly touch on the construction process of these fine models. Mr. Bowdidge currently does not offer the models, but he may return them to production. If you’re interested, contact him at: .

My first step was to drill and tap 2-56 the screw holes for draft gear and trucks. The resin with which the car bodies are printed is tough and not hard to drill, but as the kit directions advise, the drilling and tapping should be done with care to avoid any risk of breakage. I had no problem with this. 

I might mention, though, that to get threads well into the hole for the truck screws, without danger of breaking through into the floor of the car, I used a “bottoming tap,” also called a plug tap, which means a tap with cutting ability almost right to its tip, instead of tapering up the tap shaft as on a conventional tap. It enables cutting threads to the bottom of a blind hole. You can buy these from lots of industrial suppliers. To find a source, just Google “bottoming tap.” 

Next, I fitted the end sills onto the body. With just minimal clean-up with a file, these fit excellently well against the body. The kit directions advise filling any gaps with modeling putty, but I really did not have gaps. Next was drilling holes for the grab irons, to be made from the 0.010-inch brass wire supplied. But an immediate issue arose. Where are they located?

It’s clear from photos in my book, Volume 1 of Southern Pacific Freight Cars, entitled “Gondolas and Stock Cars” (Signature Press, 2002), that these cars were built with a vertical grab iron on each of the four corner posts of the body. (This is what the kit directions instruct you to install, which is fine for as-built cars.)

But in 1926, many cars were modernized, and those vertical grabs were replaced with a horizontal grab iron at each end, supported on a short post. This photo, a detail of page 44 in the book (which provides history of these cars), shows this. Note photo date, 1930. In the modernization, the side doors had been replaced with solid planking. (You can enlarge the image by clicking on it if you wish.)

This photo is also a good view of the K brake cylinder. The linkage to the hand brake staff at the nearest car corner shows a challenge for modelers: if the linkage is modeled as it shows, it will limit truck swing. I installed the linkage closer to the side sill, raising it up above the truck sideframe.

I decided to install the horizontal grab irons as shown above, using short posts of scale 4 x 4-inch styrene attached with canopy glue. The sill steps were made from A-Line “Style A” steps, attached with canopy glue. I installed a brass wire brake staff, soldered to a Cal-Scale brass brake wheel (see: ), and a brake rod from the K brake cylinder to the end sill behind the sill step (see photo above).

With these added details, and Kadee coupler boxes put into place so they can be painted with the rest of the model, I spray-painted everything with Tamiya Fine Surface Primer (Red Oxide). This not only covers well and leaves a nice thin coat, but has a semi-gloss surface that is ideal for decals. Here is the right side of the car body, in the center-dump configuration, at this point:

Note in this photo that the car body I have is the original configuration, with side doors in place. But I’ve modified the car with the rebuilt side grab iron arrangement, so my model is a bit of a compromise. 

Trucks for these cars are an interesting topic. When built, they used the early-style Andrews truck favored by SP, with a long tie-bar running under the bottom of the sideframe (visible in the photo above). In HO scale, the long-tie-bar Andrews trucks are made only by Kadee, their truck #509 or 553 (the old “sprung” versions) or #571 and 1571 (new HGC trucks, the latter with 0.088-inch wheels).

In later years, many cars were given replacement trucks, and photos show that T-section and U-section trucks of various kinds were used. But SP did keep the old Andrews trucks in service on some older cars and company-service equipment. I chose to reproduce that, since the Hart convertible cars were on their last legs when I model, 1953. Accordingly, I chose to use the #1571 trucks. 

After applying decals, and a protective coat of flat finish, I weathered the car fairly heavily. The method was my usual acrylic washes, as described in the “Reference pages” linked at the top right of this post. This is the left side; you can see the brake rigging if you enlarge the image (by clicking on it).

Many years ago, there was a Silver Streak (SS) kit for a representation of the Rodgers Company’s “Hart convertible” ballast car. I rescued one in derelict condition at a swap meet and repainted and lettered it for SP. Here is that car, which was built as set up for center dumping. It represents the rebuilt Hart convertible cars, so is taller than the Dry Creek model.

Unlike a number of early Silver Streak models, it is accurate HO scale, rather than the oversize (essentially OO scale) size found in some other SS kits. It is far cruder than the Dry Creek 3D-printed model, but does capture the overall look and feel of the rebuilt prototype, and is nice in that it has the underbody truss set back behind the side sill. I’ll just be careful not to run the two cars together!

I’m happy with my Dry Creek model of an SP Hart convertible ballast car, even though it represents a rare car by 1953. I do run ballast trains in some operating sessions, and this car will fit right in.

Tony Thompson

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