One of the fun parts of turning a bunch of 3d plans… or photos… of freight cars into a model is understanding some of the details of the design. For example, the plans for the W-50-3 Hart convertible gondolas showed some notches in the beams running through the hopper bottom. What were those for?

Some small print on the plans explains it: "5" x 9" removable center sill Dwg. No C-1852". The doors covering the hopper were wood, reinforced with metal strips, and weren't strong enough to support a full load on their own. A thirty foot 5" x 9" beam (or maybe two beams, one stretching to each end of the car) sat underneath, on top of the cross-beams, acted as support for the doors. One of the end drawings also helpfully notes that the sill would be stored behind the doors when the hopper doors were opened.

The engineering drawings for the real cars were filled with little details like this - the use of angle iron on the side dump doors, use of a bolt and a short piece of pipe to keep the door latch from swinging all the way around, and the U-bolts serving as hinges for the side dump doors. Building the 3d model for these cars requires tracking down all those details, and figuring out how to represent the visible ones on the model.

Engineering drawing excerpt from Southern Pacific Common Standard plan C-1652 "Work Car Class W-50-3", in the collection of the California State Railroad Museum in Sacramento. If you're obsessed about these cars as much as I am, call them up and ask about getting a copy of the full plan for yourself.

Hi, all, and thanks for checking Dry Creek Models out! The freight car kits you see represent a year of work. I've experimented to learn how to get good 3d printed freight cars from the Form One printer. I've made multiple trips to the California State Railroad Museum in Sacramento to see original plans. I've studied plans and photos to understand how the cars were really put together. I've also made many, many versions of each model - my layout (and reject pile) are overflowing with flat cars and Hart gondolas! I'm most excited that I can have a full train of Hart gondolas on my layout... and then share those models with all you other early 20th century modelers.

Beyond just sharing some great freight cars with you all, I'm hoping to share two lessons from these models.

The first lesson of all this work is that 3d printing gives us another way to get prototypical models on our layouts. In the 1960's, our only three choices for models was a plastic boxcar, a craftsman kit, or a long episode of scratch building. Fidelity to the prototype was less important than just getting a car that worked; getting multiple, accurate cars was near-impossible. In the 1980's, resin kits gave us detailed and accurate kits, but required tons of fiddly work to assemble flat cast resin cars. With 3d printing, we can now get accurate prototypes, and get cars that are easy to complete. For cars that often showed up in groups (like gondolas and flat cars), model railroaders need ways of getting ten accurate cars quickly. 3d printing allows us to do that. 3d printing also allows making models that could never be done using conventional casting techniques. The underframe trusses on the Hart gondola could never be done in a single piece in the correct position in either injection-molded plastic, or resin cast in rubber molds.

The second lesson is that 3d printing is now mainstream. Although the Form One isn't cheap, it's still in the range that many modelers could buy one. The models you see here show how the barriers for mass-producing models in your basement are going down. You don't need to know how to cut molds for casting plastic or be a superior craftsman to make cast resin cars. Watch for a lot of very cool cars coming out of garage manufacturers in the next few years.

In future blog updates, I'll tell you more about how these cars are built and share some new models. If you'd like to see what I'm up to on my own, check out my personal projects at the Vasona Branch blog.

Thanks,

Robert Bowdidge