Wednesday, August 19, 2015

Next 3d Freight Car Model: Southern Pacific's "Battleship" Gondolas

Boy, I've been awfully quiet lately; I'll put at least some of the blame on that 3d printer. Just to show I'm not goofing off, I'll show some of the latest work.

Here's the latest result: Southern Pacific's "Battleship" gondolas. The "battleships" were side-dump ballast cars built around 1902, and they're cool cars from so many different angles.

The Battleships are interesting construction-wise because they're some of the Southern Pacific's early steel freight cars, completely built using steel plate and angles, riveted together. They're sort of like the Eiffel Tower of freight cars in that way - big, metal, and covered in rivets, and they probably impressed the locals at the time for the same reason the Eiffel Tower was impressive. When I saw the plans at the California State Railroad Museum a few weeks back, I found they're just as interesting underneath, with a three foot tall I-beam running down the center of the car, and all sorts of cross-bracing supporting the interior A-frame for the slope sheets.

The cars are also interesting appearance-wise because they look unlike any other freight car. The available photos make the cars look big and boxy, even though they're only 30 feet long - short by modern standards, and even small for my 1930's era. The unusual hinged doors covered each side completely, and the arrangements of hinges catches the eye. Their air-operated mechanism for the side doors are beautifully steampunk with ten foot long operating levers covering the sides.

And finally, the cars were present at the Southern Pacific's greatest battles. The cars were intended to dump fill on each side of a railroad track. Three hundred were bought for the Lucin Cutoff work - Southern Pacific's attempts to tame Utah by running a railroad straight across the Great Salt Lake. They were used in the fill work to block the Colorado River's escaping of its old channel as it tried to fill the Salton Sea. The cars hauled debris away from San Francisco after the Great Earthquake and Fire of 1906. They were used in countless other improvement projects, with some cars lasting into the 1950's in maintenance-of-way service.

These cars were printed on my Form One printer, printed upside down (top to bottom) for easier support during printing. The needed support structure attached along the top rim of the car, and also had individual supports down into the interior. These versions of the model have only been painted with primer and touched up with a bit of putty; I still need to install grab irons, brake gear, and still need to paint and decal the models.

The air-operated mechanism for opening the doors was the touchiest part of the cars to design, and I'm surprised it printed as well as it did. You can see that some of the levers are supported from behind so that the car can be printed in a single piece. I found the lower frame the hardest where shallow angles support the slope sheets that stick out just beyond the edges of the car. The interiors were the fun part because they forced me to fully understand how the car was supported - posts come up from the lower frame to support the top of the car, and a different set of supports braces the door below the hinge point.

Oh, and a pro tip for folks building 3d-printed model railroad models: always take a picture with a coin or X-acto knife. Otherwise, you'll look at your photos and think "wow, that's a lousy model", and then you realize the detail you're complaining about is a literal pinhole.


  1. Robert, you continue to impress with both your research and technical prowess. Looking forward to seeing these in person some day.


  2. Hi, Bill!
    I'll be in Portland, so I'll bring them up to show.

  3. And a few of these cars received SPMW numbers. For that reason, I would certainly like to purchase one if it should become available

  4. Robert; Might the file be available to make an "S" scale model? TCC:}

    1. You've got to be quite an SP freight car fan to want a Battleship! I have no plans to distribute the 3d model; I'd like to make and sell these some day. If you're really interested, I can try putting one on Shapeways, but we'd need to figure out mounting holes and height for scale couplers and trucks. Making one of these from Shapeways FUD would be somewhere north of $125.