So I'm thinking about trying something a little different. I've been intrigued by this loco, and would like to scratch/kitbash it in HO Scale. I consider my research techniques to be be pretty solid but I'm not finding a whole lot of info on this. Knowing some of the key dimensions, I can extrapolate some of the other dimensions but was wondering if anyone has better info that what I have found so far. The drawing would be perfect, except for the fact that I can't make out a lot of the measurements. I guess on the positive side, if it's not 100% accurate, no one would be able to prove it!!!
Good luck with it. And don't let that other source fool you. All twelve drivers are 69", even the ones in the "centre".
To be fair, once the designers have reached the point of putting a joint in the middle of the boiler there's no choice of theirs I wouldn't question!
I've had this project on the back-burner for years too. I think there may be an old thread or post about it somewhere on here. I got the running gear built, but that's it. It's a pretty embarassing attempt when I first started working with styrene. The IHC Pacific drivers are the correct diameter, and the wheelbase is within inches, so that's what I used as the base of the project. I think about the project from time-to time and try to refine the concept. My current plan is to either 3D print or scratchbuild the chassis, but have the boiler turned from brass stock. I could build the entire locomotive from styrene if I wanted to. At this point in my career, I have the skills to do it, but it wouldn't be heavy enough to pull well. I need more experience with brass if I want to make a steam locomotive. The drawings that Tulsa shared are reproduced in Iron Horses of the Santa Fe Trail, along with some other good photos and history. It's also worth researching the 2-10-10-2 and other early 1910's ATSF steam locomotives. The railroad shared components across many of those classes, so information about things like fireboxes or tenders can also be applied to the jointed boiler locomotives.
There's also this drawing; again looks the same as Tulsa's folio drawing, but now in one piece. There are also many other ATSF steam recognition drawings on this page. https://www.kansasmemory.org/item/221763/page/225 One thing to keep in mind is that the boiler diameter on the drawing is most likely the inside diameter. When you account for the lagging and the boiler jacket, the final diameter you see is going to be a few inches larger than the drawing says. This is where I got hung up on my previous attempt. I wasn't sure how thick the asbesos insulation would be. I'm sure data on steam locomotive boiler jackets is out there, but I'm not a steam guy. This is just a novelty project for me, so I don't know all the intricate sources for information like that. Based on locomotives that have been de-jacketed at train museums, I'd guess it's around 2 or 3 inches thick from boiler inside to jacket outside, which is enough to throw off the general appearance of a model. The flexible boiler locomotives are relatively long and slender, but you don't want them to look too slender.
Great points. I'm in the starting phase so it'll be a while before anything worth showing is created. I did buy the book you mentioned and i'm looking at picking up a couple of the RSO/IHC/Mehano Pacifics as a starting point. This pic is great. I'll be able to scale it to 1/87 and have a nice plan to build from. I really appreciate the info as I'm not as skilled on steam as I'd like to be.
Another one I almost forgot about is the February 1987 edition of Trains Magzine. The cover issue is all about ATSF 2-6-6-2 Mallets (standard and jointed boiler). There aren't drawings, but there are some good photos and a lot of historical information on the subject. The ATSF Historical Society magazine Warbonnet may also be a good source. I see a few articles about articulated steam, but I have never read the magazine. It may be worth emailing the organization to see what the articles are about. The deGolyer Library at Southern Methodist University houses the remaining Baldwin Locomotive Works drawings. Most of the collection was destroyed when the company shut down or stopped making steam locomotives, but a few people personally saved drawings that were being disposed of. That makes the collection very piecemeal. The index is online, and it looks like they have one drawing of a 3320 class (I think 20, 21, and 22 were the flexible bellows type) I emailed them yesterday, and they said it was a cross-section (so you see the circular profile of the boiler at different positions along the length of the locomotive). This could be useful when shaping the boiler, steam chests, or cab. The lady I talked to said scans were 40 bucks. I have a million other projects already half-finished, so I have to complete these other ones before I can start funding a new locomotive. Or maybe I'll change my mind in the next few days and just go for it. This drawing is probably the most detailed extant blueprint for the 3320 class, much more than the basic folio drawing we have been looking at so far. I haven't seen the drawing, but she attached this other drawing as an example of what it looked like: https://digitalcollections.smu.edu/digital/collection/rwy/id/3918/rec/2
