What were they used for?
They still are. Trailers and occasionally containers.
The idea is to minimize tare weight, the amount of structure you aren’t being paid to transport. In the '60s and '70s the idea came in vogue of using cheap trailers on very lightweight cars – there were even a few 4-wheel cars proposed, and pre-Wickens the suspensions they tried were criminally primitive. With this came the age of sideloading with power equipment, mostly done with machines like LetraPorters and PiggyPackers that were touted as being able to take any old trailer and whisk it on or off from the side, with full random access, in a few seconds. (It would turn out they would usually damage trailers, if not sooner then later, and to this day special, expensive, tare-increasing reinforcement is necessary…)
About the apogee of the spine car was the ATSF FuelFoiler, from the age when 90mph freight trains were ATSF’s demonstrated distinctive competence. These were about as lightweight as practical: a 10-section rake articulated in the centers with no deck – only lowered pockets for a trailer bogie and a hitch for the kingpin. This would lower the trailers for the lowest air resistance and reduce sway and give lower CG on curves. Of course trailers had to be lifted on and off (no circus) but that was an acceptable part of the ‘weapons system’.
Before anyone gets hyped about 2 axle cars
Yeah, but we never had a real two-axle design that made any particular sense. You need to look at the real HSFV as a starting place… and not the built-to-a-price cheapened version that came later, either.
Axle vs. coupler spacing to be determined by the Bissel formula for guiding.
As usual, I’d love to read Mr. Goding’s opinion on Wickens and what might constitute a stable four-wheel container platform for use in a unit train.
American railroads and their equipment are all ‘built to price’.
But HSFV was not particularly ‘expensive’ by North American standards … just carefully engineered and correctly proportioned. It would have been highly interesting to have tried something like that around the time we imported the 100mph Leyland railbus for the NEC… it would have needed very careful damping and compliance in the ‘coupler swing’ arrangements to be right, but that wasn’t even rocket science in 1980.
1980 - the money was being funneled toward mergers and acquisitions - not new technologies.
I can’t say that I have any experience with single axle bogies although I did propose a 3 single axle bogie switcher when we were trying to make a cheap locomotive in the late 80’s. Fortunately, it was still too expensive to make a sale.
At the risk of sounding flippant, the performance and reliability of Koni yaw dampers today can really make any suspension stable at NA freight speeds - The HTCR truck has a low yaw stiffness on the end axles and those axles will hunt at a very low speed without the primary yaw dampers and that isn’t fundamentally different from a single axle steering bogie, particularly with the interaxle yaw connection now removed from the HTCR. As others have pointed out, however, the ability to equalize wheel loads is critical and given the longer length of NA vehicles, coming up with a suspension that equalizes at empty condition while not having too much change in coupler height loaded I think is the bigger challenge.
Dave
TTOX cars were a nightmare, especially when empty or switching.
They were also a operating nightmare - under any conditions.
The only one’s that could have liked them had to be the bean counters, and only when they looked at the costs of construction, not when looking at all the other costs associated with their use and operation.
They see the savings that they want to see. They don’t see the costs that they don’t want to see. That hasn’t changed and probably never will.
Jeff
There is nothing flippant in the least; it’s fundamentally true, at least at the polar moments and speeds involved at anticipated ‘economical’ freight speeds. I thought it a little amusing that so much research and sometimes ‘crackpotted’ ingenuity went into three-piece-truck yaw-damping experimentation in the Fifties – some of it very properly progressive but with detents on centering – before constant side bearings (and their strategically-advantageous short-period ‘friction’) ran away with the effective market.
Where Wickens is notable is that he designed for primary yaw stability, a bit like what Stroudley thought he was doing on the Gladstone 0-4-4s. Then instead of accommodating natural instability with intelligent brute force and charm, as in properly valves and tuned Konis or horizontal active suspension, you make the physical running gear self-correcting. It came as a great shock to me that a solid-axle wheelset with taper was dynamically better than Talgo-style separate wheels in this context, and it was not fun having to explain to someone with an ingenious patent to separate wheel rotational speed on a ‘drop-in’ replacement wheelset for three-piece trucks that there would be no miracle guiding improvement…
Progressive compliance and yaw damping in Bissel leading axles has been a fascination of mine from comparatively early on. I am still uncertain as to how well the LS&MS Prairies did this – supposedly well, where othe
I have yet to hear a hogger who enjoyed these in their train… From being too light. Hunting at track speed. Derailing quite often when MTY. Even TTX was happy when these got scrapped. Great concept, just not the concept for North American HH.