I have a friend that wanted to know how much of the prototype wheel on a locomotive actual makes contact with the rail. I figure there must be a relation between the size of the wheel and size of the rail. Can anyone answer this question or point me to a link where I could find that answer.
The contact has been shown to be a small oval shape or ellipse, and the long axis runs parallel to the rail. It is something like 3/4" long and maybe 5/8" wide.
Keep in mind that the size and to a small extent shape of the contact patch depend on the diameter of the wheel and the actual load on it. You may have noticed that the inner wheelsets on most articulated spine cars have larger wheels: this is a mojor reason why. Steam-locomotive drivers are an even further example.
Yes, part of this is elastic deformation of both the railhead and tread.
Shape varies slightly depending on taper and whether any of the flange fillet is under load. Of course it varies more dramatically in curving and when actual flange contact occurs, but I think that's beyond the scope of what you were asking
When discussing this with our passengers, I tell them the total contact between a car or locomotive and the rail is less that the area of a dollar bill.
I recall reading some time back that the railroad industry discovered that wheels took on a certain profile after running for a bit, and that they rolled better with that profile, so the railroads started turning wheels with that profile instead of a flat taper.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
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