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I’m just guessing that the amount of lateral displacement at 3-5" UE would be about the same for the Rohr and UA/Pullman trains. The geometry of conventional suspension is limited in movement by the smaller dimensions within the truck.
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The Rohr trains were widened versions of the ANF Turbos built to the French “loading gage” that ran in the Midwest on routes out of Chicago and would have a width similar to the UA/Pullman Turbo Train.
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While I’ve read about the lateral displacement issue for the New York-Boston line, there was nothing mentioned that I’m aware about that issue for the New York-Buffalo line where the Rohr trains were deployed.
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Other problems such as low hours of service between turbine maintenance and platform incompatabilities eventually doomed the UA/Pullman Turbo Train in the East as pointed out previously in this thread.
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I too read about UP allowing 4.5" UE for outside swing hanger trucks. Of course, this design is too costly for Amtrak to buy and maintain - better to go with inside swing hangers! (sarcasm) Actually, Amfleet and post-war Hiawatha cars employed a variation and predecessor to the outside swing hanger.
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With 3" superelevation (cant), the Hiawathas were allowed a comfortable 100 mph with steam locomotives. Eventually the maximum allowed speed was reduced to 90 mph with diesel locomotives, ostensibly because of quicker acceleration. Maybe the superelevation was reduced for less wear by heavier freight cars. Eventually, the Milwaukee Road was granted permission to remove cab signals and reduce the maximum allowed speed to 79.
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Today the CP freight limit on the Hiawatha
The January, 2009, Trains has a picture of the “Acela” turbine locomotive sitting among weeds in Pueblo. Sadly, this is perhaps the only American passenger locomotive that bears a large American flag.
The comment about Hiawatha’s being scheduled for 100 mph operation more than a half century ago using steam locomotives is sad also. Those locomotives were beautiful! No wonder why I frequently lament the absence of pride in our passenger rail system.
The Acela gas turbine may find a home in the Midwest. Illinois and Indiana may have a few 10-20 mile stretches that could be cobbled together to allow up to 150 mph running with at-grade crossing elimination and grade separation and limited curve easement.
The trickiest part would be to avoid passing tracks that would render a 150 mph zone useless without a second main track.
I would be interested to hear from Jerry what he thought of the capital cost to maintenance cost ratio of the light alloy steel bodies used in the Rohr turboliners. Since he was involved in the overhaul of the trainset he should have a pretty good fix on the condition of the equipment at the end of the original service life. I guess my question is why do we feel that we have to do things so different than Europe with regard to the carbody design.
The alternate way of achieving a flat surface was really intriguing but I understand something like this is fairly common in European stock. Experiments like the use of Alpolic composite panels for the finish surface and insulation are also interesting. Just think of all the advances in intercity bus bodies that have been made with structural silicone adhesives, welded tubular frames, and composite panels. Then consider the price point for a motorized bus versus a passenger railcar.
With regard to the unbalanced elevation do any of the other posters know of a modern attempt to reduce the roll angle of a standard carbody to near zero using passive means (modern swinghangers). I have wondered if the airspring bolster could not be fabricated so that it had vertical struts under the airsprings that would allow the airsprings to sit within a pocket above the floor of the car. This bolster would not rotate about the truck vertical axis but rather would be kept in place with a drag link. The truck sideframes would bear on long travel bearings that would rest on this bolster.
The result would be a roll center above the center of gravity that would be entirely passive and somewhat simple. With elastomer journal springs this could pave the way for a high unbalance replacement for the Amfleets that will be needed soon. I suppose Europe has no need for such as they are already allowing 5-6" unbalance with standard coach stock which is why this would have to be a north american innovation.
Finally, I have to applaud Jerry as it is certainly difficult to a
The vertical strut you wonder about is close to the Talgo patent.
As I recall but had no quick success Googling, the TGV employed long-travel springs between a bolsterless truck and a body support point above the floor on either side of the gangway between articulated cars. I have no idea how lateral motion between the truck and carbody was controlled - gravity? snubbers? control links? The current Bombardier catalogue features “Flexx” bolsterless trucks and suspension seemingly to avoid maintenance, weight, and complexity of bolsters and swing hangers for everything from trams to locomotives.
The only elastomeric primary journal suspension currently offered by Bombardier is for metro trains. I rode the X2000 when it was on demonstration and was very impressed with the ride and concepts to achieve low unsprung mass. The elastomeric journal springs were replaced by steel coil for the last X2000 version I saw Googling the X2000.
I rather doubt 5-6" underbalance is allowed on any wide-spread basis in Europe. It’s been a while, but an SNCF official told me that practice was restricted to all reserved seat, extra-fare trains for standing passenger safety. This practice may have all but disappeared with the completion of high-speed networks diverting the market.
VPayne’s description is a little hard to follow. There are two general kinds of passive tilt. Talgo relies on placing airsprings on the tops of tall posts on top of the axle journals – it is not clear to me if Talgo ports air between the air springs to control the tilt or simply lets the car body roll against air springs with a fixed charge. The UA TurboTrain and Train-X (NYC XPlorer, New Haven Dan’l Webster) used a four-bar linkage remote roll center arrangement.
You can easily place the roll center of the car body any place you chose by simply angling the swing hangers. The problem with this approach is that the swing hangers are short because the space underneath the carbody is limited. As the car rolls, it also jacks up, limiting the percentage of the side force that gets compensated by passive tilt.
What the guided-axle arrangement (Talgo, Train-X, TurboTrain) buys you is that by placing the axle between the train cars (or at in non-revenue space at the end of a train car), those roll links can be much longer and you can get more passive roll compensation. In fact, the TurboTrain and Train-X links are inverted from the swing hanger suspension, and these trains are unstable and would flop over were it not for elastomeric torsion springs.
Hitachi has a patent on an alternate passive tilt arrangement where they use a bolster that has wheels that roll in a circular track, the center of which is the remote roll center. The augment this passive tilt with pneumatic cylinders, and this is the narrow-gauge tilt train (3.5 foot gauge) that tipped over in Australia when a driver failed a speed restriction on a curve.
Re Tilt in Europe:
I don’t know where my brain was when I wrote that Talgo was the only tilt system in Europe. I’m very familiar with the Pendolino ETR having been privileged to ride it on a private demonstration run from Arrezo to Florence in 1987. Maximum cant deficiency was 15 inches and speed was in excess of 100 mph. Great ride. The doors were open between cars, permitting a view of the adjacent car’s tilt entering a curve.
My experience in France is somewhat dated but when I was interfacing with ANF in the 70’s and 80’s, SNCF’s philosophy was to run the TGV’s on very good straight track where tilt was not required. On the smaller 125 mph lines on which they ran the RTG’s, cant deficiency of 8 inches was considered acceptable. ANF designed a tilt system but, to the best of my knowledge, never applied it. I’m sure they now offer the Bombardier system
In 1988, the Coalition of Northeastern Governors (CONEG) and Amtrak conducted tests between Boston and New Rochelle to determine whether tilt would permit higher speeds in the Northeast Corridor. An Amfleet train was used as the baseline. Trains tested were the Canadian LRC, Spain’s Talgo, the French RTG and the Rohr Turboliner. Cant deficiencies from 4 inches to 8 inches were tested with the non-tilt trains while the LRC was tested up to 9 inches and the Talgo to 8.4. I rode all of the trains during this pro
Re Capital Cost vs. Maintenance Cost
I’m not able to generate actual cost ratios for the mild steel vs. light alloy steel as a car body material. I can say, however, that the RTL bodies were virtually rust free when the paint and “Bondo” were sandblasted off and the floors and underframe were solid. As I noted previously, the finish could have been spot repaired at a major cost saving. From a strength standpoint, the trains are good for another 20 years if they ever get back in service. As matter of interest related to another program, I had a qualified person inspect a number of the RTG Trains in France after they were retired. These were also in good condition.
At its birth Amtrak inherited most of the passenger cars the railroads had not already scrapped. Rohr had a contract to restore and refurbish any of these worthy of the effort. This was done at their facility in Mira Loma, CA.
The cars built of mild steel were totally rusted out. Inspectors evaluating them were warned not to set foot on the floor if they did not want to fall through to the track. Restoration was not deemed economic and these cars were generally scrapped with the exception of the trucks and couplers. The Budd stainless steel cars were still very solid and these were restored, refurbished and put back in service as Heritage cars. The only fault with the stainless steel car sides was that if they
In Europe, a lot of tilting trains have been tested, the last one was a version of TGV developped for test in Franch central Mountains. This version was stopped when Alstom bought Fiat Ferroviaria. Since this time, Talgo and Alstom (with Pendolino) are the reference of tilting trains. Siemens can propose also this solution and I believe that high speed connection between Madrid and Lisboa will be tilting train manufactured by Siemens and CAF.