7j43k Paul of Covington Speaking of wheel slip-- with zero taper on the wheels you are depending solely on the flanges to keep you on the track, so would it be advantageous to have the wheels free to turn independently on the axles? This way you are not forcing the wheels to slip on the curves. I'm not sure, but I seem to remember reading that Talgo (or maybe it was somebody else) wheels are designed that way. You "can't" because the wheels are powered. They are driven by only one traction motor per axle. You would then need two motors per axle. Which is certainly possible, and maybe even a great idea. But I don't think anyone's done it. Hey. Maybe I invented it. Dibs! You would also need, I think, really good motor controllers, so as to keep the two motors appropriately matched. Ed
Paul of Covington Speaking of wheel slip-- with zero taper on the wheels you are depending solely on the flanges to keep you on the track, so would it be advantageous to have the wheels free to turn independently on the axles? This way you are not forcing the wheels to slip on the curves. I'm not sure, but I seem to remember reading that Talgo (or maybe it was somebody else) wheels are designed that way.
Speaking of wheel slip-- with zero taper on the wheels you are depending solely on the flanges to keep you on the track, so would it be advantageous to have the wheels free to turn independently on the axles? This way you are not forcing the wheels to slip on the curves. I'm not sure, but I seem to remember reading that Talgo (or maybe it was somebody else) wheels are designed that way.
You "can't" because the wheels are powered. They are driven by only one traction motor per axle. You would then need two motors per axle. Which is certainly possible, and maybe even a great idea. But I don't think anyone's done it.
Hey. Maybe I invented it.
Dibs!
You would also need, I think, really good motor controllers, so as to keep the two motors appropriately matched.
Ed
Thanks, Ed. I didn't realize that all wheels were powered. I should have thought, "subway", rather than "train". I suppose you could rig an automobile style differential, but that would add weight and complication plus a little loss to friction. Oh well.
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"A stranger's just a friend you ain't met yet." --- Dave Gardner
Again, I'm not an engineer, so I don't know for sure what the explanation is for why the corrugation would be less in locations where trains regularly brake. One reason, I suppose, is that the suspension system may not be as free to move during braking. There is also an energy transfer going on during braking between the train and the rails, which may have some effect on the wheel-rail dynamics. Whatever the reason, something must be happening during braking that reduces the corrugation.
By the way, I live in the Chicago area and the CTA rapid transit has had the same problem, although it's not as bad today as it used to be. But it was really bad when CTA used PCC 'L' cars that didn't have much sound insulation and had open windows in warm weather. CTA, at one point, touted a special rail grinding train called the Sh-h-h-hicago as a solution to this problem. It did make the track quieter. But it also showered the track and surrounding neighborhoods with red hot grinding residue that started fires, so it was quietly retired. The CTA trains were also much quieter in areas (particularly approaching stations) where trains regularly braked.
With respect to the comment suggesting that non-tapered wheels might be more susceptible to derailment than tapered wheels, that was definitely not true of the North Shore Line, which used non-tapered wheels for decades in high speed service. The very reason they used this design was to reduce the chances of derailment by reducing the severe truck hunting they were experiencing with traditional tapered wheels. Also, I don't know whether this is true, but I've been told that CTA still uses non-tapered wheels.
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