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Great info there. I've always wondered how those trucks actually worked. I knew how they looked from the side and obvisouly they had to function but that was as far as my knowledge went. One of those things I was going to research when I got a "round tuit" but just never did. Thanks to you I now understand the design.
--- In STMFC@..., "brianleppert@..." <brianleppert@...> wrote:
This is in response to Tyrone Johnsen's post from eight days ago:
These are Swing-Motion Caboose trucks. Swing-motion trucks differ from conventional trucks in that the truck bolster and spring plank never touch the side frames. Rather, a Transom connects the two side frames. The transom is open in the center from the top thru the bottom. The spring plank hangs from the transom by four links. The springs sit on the spring plank and the truck bolster sits on the springs.
I have added three illustrations from a Bettendorf Co. brochure to the "GN Caboose Trucks" file on the Photos section. These show Bettendorf's Swing-Motion Caboose Truck, their cast Transom and a cross section view which I hope will better explain how these trucks are set up.
Notice that the center line of the leaf springs are inboard of the side frames. This is why less of the leaf springs are visible from trackside.
The transoms on GN's cabooses are kind of crude looking, IMO, and GN was using freight car truck side frames instead of special ones as on the Bettendorf trucks. Perhaps Great Northern fabricated these trucks themselves? AFAIK, these are unique to GN.
Tahoe Model Works
Carson City, NV
--- In STMFC@..., "aaejj2j" <tyrone.johnsen@> wrote:
I have posted four prototype photos and one model photo of an Andrews truck as used on the shorter GN cabooses in the Photos section in a new file called GN Caboose Trucks. Of interest here is the spring chamber area. I am interested in information or thoughts on the approach the GN used on these caboose trucks. The GN had similar caboose trucks with "Bettendorf" T-section and perhaps U-section sideframes which utilized the same or nearly the same spring chamber. About up to 1940 the GN cabooses generally used archbar trucks but these 25' wood cabooses were upgraded about in the 1940s and received new trucks, generally Andrews and Bettendorf T-section sideframes. The 1945 and later 30' cabooses like the Ambroid, Northeastern, and PFM Tenshodo models had U-section sideframes with similar spring chambers. I wonder if this approach was unique to the GN or if others had similar trucks. The trucks have a 5-0 or so wheel base and probably came off older freight cars which might have gotten newer trucks of higher load capability. The spring chamber appears to have been flame cut (on the ends) out of a box section of steel. The bolster is seen farther inward.
I photographed this on a car on private property in MT along US 2 and the old GN tracks; but from photos I have seen it is representative. Some older photos may show a sheet metal over the area above the springs. Note I added a plastic foot long ruler to help me determine various lengths.
Of course what I have been trying to do is improve the trucks on my cabooses as I do not like the brass trucks for operation and no plastic framed trucks look correct. Most model trucks are longer wheelbased and if they have real springs their spring chamber seems unrealistically wide. Trucks such as CV or Kadee are often modified with the old Walthers, Silver Streak, Kemtron (I think I have all of these) metal springs result in the springs protruding too far outward, visible bolster end, and too wide a spring opening and without the appropriate enclosure. I have modified some model trucks as IM. I have many more photos and some with dimensions added and some of various model trucks and conversions for those who may be willing or interested.