The Pennsy knew a little something approximately 90 years ago. They created an experimental bogie which was ahead of its time (here’s a link to view it). You’ll notice it has an inside frame instead of the curent outside frame which is currently the standard. Tapered roller bearings were just coming onto the scene, and this bogie had them albeit axle equipped. However industry wide adoption had not taken place.
Fast forward to 2021… Tapered roller bearings are the norm and anything else is uncivilized. 90 years ago Pennsy knew lighter bogies were a benefit. Looking at the truck above you’ll notice the decreased bolster size. Which tends to be one of the heavier components in a bogie. Back in 2019 a small startup named Advanced Truck Systems created a newer concept of the inframe bogie. The difference is the ATS bogie is a 2-piece bogie, versus today’s and Pennsy’s experimental 3-piece.
A 2-piece bogie holds many advantages over the current design. Better curvability, tracking, lighter weight for greater net capacity, and cheaper construction.
I guess the old saying holds true in all facets of life. There’s nothing new under the sun.
I wonder if the sheer expense of re-equipping compounded with the Great Depression caused the PRR to shelve the idea? It seems like it had real promise.
Those designs would certainly make brake shoe inspections a lot easier. On most freight trucks today, the brake shoes are almost completely obscured by the truck frames.
Agree about the brake shoe advantage of the inboard bearing truck but there’s disadvantages too. One is roll stiffness and damping of the suspension - with the springing inboard of the wheels there is much lower roll stiffness for a given vertical stiffness. This can be made up with supplemental roll stiffness devices but that’s an added complication. Another is wayside hot bearing detectors, to my knowledge they are all aimed at the bearing outboard of the rails. The AAR standard S-3007, in section D, defines at target area for the detector outside the wheel so any inboard design could not comply as currently written and would require an investment by the RR’s to add inboard detectors. I am guessing all inboard bearing passenger car trucks have onboard bearing temperature detection systems to get around this, and I suppose with all the work done to add monitoring systems to freight cars that could be done here.
I’ll add a rant about what I observed during my 3 years working on freight car truck design at ASF-Keystone. When a company develops a proprietary design for a new truck or component, the AAR stalls their approval of that device for interchange until a competing design is available to be able to pit suppliers against each other to get leverage and the lowest price. The biggest I saw was the articulated connector ASF developed for stack cars - it was such a great innovation the RR’s didn’t wait for AAR approval and handled it by inter-line agreement rather than wait for AAR to write a standard and grant approval for interchange. Same with yaw dampers. You can be sure AAR would not approve an new inboard bearing freight car truck for years, maybe decades.
Yes electronic monitoring of the axle bearings is in order for the ATS truck. For as much as the AAR touts the rail industry and its benefits. Somewhat surprising to hear them holding back progress on connectors, advanced trucks, and suspension systems…
Pretty sure they knew that they are called trucks. Bogey as in railroad use is British. Bogey as in the wheels on a tank refer to two wheels, not four.
At EMD, truck and bogie are used interchangeably. One recent group manager insisted calling it the “Bogie Group”. Didn’t manner to me, understood either way.
No, this appears to simply have rubber shear pads at the bearing adapters allowing some axle motion to steer itself, with steering arms coupling the axles. This is really the same as an AAR M-976 truck re the shear pads with steering arms based on List design. The big advantage of the ATS design is the high warp stiffness compared to a 3-piece truck which limits parallelogramming of the truck.
It’s over two years old. I haven’t found any info on them being tested under a railroad car, yet.
Nor do I find a company website, containing further information (like truck weight).
Looking at the photo, I’m wondering what the brake beam assembly (in yellow) pivots on. It appears in the photo that it’s not even attached to anything.
Here’s a drawing of the truck:
No brake beams are present. I also see what looks like a rubber air spring bag. Or whatever it’s called. Is that acceptable on a freight truck?
The spring between the bolster and sideframe looks to me to just be a rubber spring with a shape to give it a lower stiffness when unloaded and a much higher stiffness when compressed an inch or so. The bolster slides against the car bottom on plastic pads where the side bearings would normally be which gives it high friction yaw damping for stability. It looks to have steering arms attached to the bearing adapters that connect in the center under centerbearing like the Harold List truck which was licensed to Dresser as the DR-1 then later to ASF as the AR-1 when they bought Dresser. It’s not visible but I think each sideframe has member going transversely across to the opposite sideframe which creates the warp stiffness. The sideframes can pitch independently providing wheel load equalization like a 3-piece truck.
Putting the rubber spring directly under the bolster end with the sliding wearplate directly above it was taken from a patent I got while at ASF seen here:
Reminds me of the reasoning for applying roller bearings first to freight cars that stayed on-line: the owning railroad got the benefits, rather than some OTHER railroad (when the car was off-line).
Will ANYONE buy these? I’m sure the designers and builders of these would like to get some monetary return, perhaps enough to break even.
I completely missed your point! I watched the whole clip waiting for any mention of anything train-related, then it hit me. (I’m not much of a movie fan.)
That’s OK, sometimes it takes me a while to get the point, or a joke. But you got it, that’s what matters. Personally I’m not much of a current movie fan, the last one I saw was “1917.” The rest of the stuff they put out now doesn’t interest me at all, I’d rather watch the classics.