Sunday, April 1, 2018

3d Printing A Crowd of Passenger Cars: Harriman 60-C-1 to 60-C-4

In any operating model railroad, the engines and the cars are the characters in our play. And just like in a play, crowd scenes need a crowd - only in this case, our crowd are lots of trains and lots of freight and passenger cars. Collecting enough rolling stock for a model railroad can take a while as we build kits, shop, and otherwise put together an appropriate set of rolling stock for our layout.

On the Vasona Branch layout, I’ve accumulated my freight cars over years, slowly getting just the right mix of cars. The layout started out with some freight cars from my teenage years. A few years out in the wilderness of suburban New York City got me a bunch of PFE refrigerator cars, all picked up at Valley Model Trains's great location out at an abandoned mill in Wappingers Falls. I’ve bought and built additional models - some resin, some plastic, but all trending towards the era I chose. I’ve gotten rid of unprototypical cars, bought others that better match my 1920’s California setting, and now my layout has the depression-era look of a sea of brown boxcars. I’ve got my crowd scene.

With the Market Street layout, though, I’m back in the position of not having enough characters for my crowd scene. This time, my problem is a lack of passenger cars rather than freight cars. I haven’t had to model passenger operations significantly in the past, so I don’t own a lot of equipment. And I need a crowd.

My current Vasona Branch layout, after all, only needs two passenger trains - a Los Gatos commute and the Santa Cruz to San Francisco train. The commute is served with some ok 1980’s, Soho brass commute cars. The Santa Cruz trains use a string of 1960’s Ken Kidder cars. Both cars aren’t particularly detailed, but they’re affordable ($100 for the Soho cars, and $40 each for the Ken Kidder cars), take well to modification, and aren’t particularly rare so they’ll turn up on eBay if I’m lucky. I’ve got an assortment of other passenger equipment - baggage cars from the old MDC kits, a Southern Car and Foundry 70 foot baggage car that can’t quite make it around my 24” curves, and one or two odd brass cars - but otherwise that’s it. Great for a branch line out in the country.

The Market Street layout, in contrast, needs a crowd of cars. It needs four or five commute trains, each with at least three cars. It needs several baggage and postal cars that will be added and removed from some of the commute trains. And it needs at least a train or two to represent long-distance trains passing through.

That’s a lot of cars - fifteen or so coaches, four baggage cars, four RPOs, and another train set or two.

Well, I’ve got a 3d printer, and I’ve already made freight cars on it. What could be so hard about making Harriman cars?

These models represent the 60-C-1 to 60-C-4 Harriman passenger cars built starting in 1910. The actual cars were the first steel cars for the Southern Pacific. They ended up in wide use across the SP system. More importantly, they were common cars on both the SP commute and short-distance trains such as the Santa Cruz to San Francisco run. The cars originally had gas lighting, but switched to electrical lights by the late 1920’s - a key detail to add for later cars. The 60-C-1 to 60-C-4 cars were only the first Harrimans; there were other series (both as plain coaches and more comfortable chair cars). But these earlier cars were near-identical and look better to my eye. Later series had different window heights or spacing, differences in doors, and a bunch of other minor differences.

These photos show the first two presentable cars I've 3d printed. There's still some details to get right, and there's still some challenges in assembling them precisely, but these models do show that a crowd of passenger cars can come off of a 3d printer.

The cars have been a bit of a challenge. The cars are too long to fit in the printer, so they had to be made in sections that I'd assemble into a single car body. I ended up making the cars from four pieces: a vestibule and car end, the body in two halves, and another vestibule. I printed the bodies vertically, just like I’d done on the flat cars and Hart gondolas. This meant that only the cross section of the car was supported, minimizing support structure and keeping the support structures off of finished surfaces of the car. The car ends couldn’t be done this way; they print upright, with the support structure attached to the steps and to the coupler pad. The bottom ends up being coarse because the side facing the build platform never quite prints right because of lack of support, but the overall part prints fine.

Like all the 3d models I’ve done, the cars are also challenging because of all the niggling little details I need to understand in order for the car to look right. For example, the roofs on Harriman cars were overlapping steel sheets. The lower sheet always was placed between windows; the top piece always lined up with the windows. That’s a trivial detail, but needed to capture the look. Minor inaccuracies in window spacing is a glaring problem for anyone who's researched the car. Getting the roof curve correct took multiple tries, and I'm still not quite happy. Other little details - like the beading at the intersection of the roof and side - turn out to be more important than I expected. Without the beading, the cars looked wrong, and it was hard to spot the point where the roof curve ended. It also was helpful for brush painting - the brush could be drawn across the bead to paint it neatly, and the bead would stop the brush from going further. I could cheat on any of these details, save myself a bunch of time, and have complete cars sooner... but they wouldn't look right to my eye.

Enjoy these photos of the cars and the pilot models; I’ll talk in-depth about the cars and their construction in upcoming posts.

Thanks to Jason Hill - his experiments using Shapeways to print wall sections for MDC Harriman cars inspired me to try making a whole car.