Have been looking many years through “Trains Mag” but have never seen a blue print type of drawing of the HTC-R truck. Seen a photo once and it appeared to have a large bar going across the top. The main pivot point didn’t appear to be above the center axle. It appeared to be between the second and third axle and large flat area between the first axle and the second axle. The first axle facing the fuel tank which hold the traction motor support point and the open end with third axle exposed. The axles are a flotation design and are not kept ridged in place like other truck designs. How do they keep the axles aline with the rails and not derail in the curves when under load. I remember a truck design that EMD experimented with a design where they cut a “c” truck end axle off put it back to back with another of the same design truck. There was a large bar that ran along the outside of the frame where it went from the frame to the truck foward and backwards.This design would have 4 powered axles and would seem like a very radical design to use but never seen any more about it. I guess it didn’t work out so they didn’t continue work on this design. This design proceed the HTC-R design as I recall.
If this is the EMD truck design, see here for what may be the level of detail you need.. There are also patent drawings that show the principle of the radial steering quite well, although diagrammatically (4,679,507 and 4,765,250 respectively, to get you started).
See also the Henschel 'Flexi-Float" design for more on floating axlebox designs, and the GE ‘rollerblade’ trucks for an illustration of how axleboxes can be made to ‘float’ without locating linkages (wing axleboxes have a long and fairly illustrious history…)
GE has a different approach to radial steering, which is the design that has the bridging bars across the outside of the truck frame, as seen for example on many of the 6000hp locomotives. There is a patent explaining this, too, which I think is 6,006,674.
I’m sure that Peter (M636C) will have a great deal to contribute to this thread when he sees it.
Overmod : this is the best information I’ve seen so far about the HTCR truck. I have gone to the EMD website but cannot find that information that you found. This truck seems more complex than most other truck designs, have they had any reliability problem because of so many moving parts? Have they ever tested the HTC against the HTCR to see how much difference there is in the traction control of each of the trucks. Thanks for the information , it was one the the many things I just wanted to know about.
Many recent orders have been built with a new rigid truck, I think in part based off the HTCR.
I was on the EMD test car as support for part of the testing of the HTC vs HTCR trucks that was done in the late 1980s on Raton Pass using strain gage outfitted wheel sets. (I also built the prototype electronics for the test) The test unit was one of the SD60 demonstrator units. I don’t know the technical details of the results but can tell that the HTCR trucks are as advertised with less wheel wear. I also was somewhat involved in the testing of the 4 axle articulated steering truck, applied to a BN SD40P locomotive. I’ll see if I can find my picture and post it here.
Found a nice picture of BN 6599, but I cannot post it here, Sorry!
doug u----- slightly off topic, were Bert Hefner and Bob Konsbrook still around when you worked at EMD or had they (long?) retired? How about Rudy, forget his last name, ex-German Rocket scientist?
Daveklepper l never worked for EMD, just have an interest in trains. I work on jet engines for a living (PW2000). Trains are just a Hobbie that I am interested in. I have been reading “Trains Magazine” from about 1964 on and try to keep up on the latest changes that are happening in the railroad industry. I become somewhat interested in steam locomotives lately and trying to understand how they work.e I have a friend who thinks they should bring back the steam locomotives , and I tell him that will never happen. Diesels will never be replaced with steam -never). GDMRM Co Found the picture a picture of the strange truck that I saw in “TRAINS” The magazine didn’t really give much detail about that truck other then they are testing it. That design should give the locomotive a high amount of pulling power, 8 axles to work with (two sets of trucks). I think that truck design just looks ‘cool’ . That would be hard to model this truck design in HO scale. EFCO It sounds like you worked for EMD so you would have the inside track as to what happened with those truck designs. The testing must have been very interesting to find out if all hardwork in design of the truck would pay off in with more pulling power, less wear on the rails, and other benefits that would save money for the railroad. Just was thinking where the next big improvement will be coming from in the locomotive development group. I was thinking if they ever put a jet engine in to a loco like the “big blows” it would have to be about 20,000 hp.(CFM56). It would take two 8 axle loco to use that much hp.
Apologies, my question regarding Bert Hefner and Robert Konsbrook should have been asked of EFCO!
Bert headed electrical controls development and design, and Bob, a railfan and CERA member, special projects and testing. Rudy was in diesel technoloogy.