How do train cars go around curves [trainTrivia]?

Question

Consider this: the wheels of a box car are solidly attached to their axels,always turning at the same revolutions per minute as the axel. As the train enters a curve the outer wheel must turn faster than the inside wheel . Neither wheel can slip on the rail or extreme wear would result due enormous weight. How is this accomplished? I have asked this question many times over many years and only had one correct answer. Railroaders disqualified!

Answer 1

If you've already had a correct answer, why are you asking again?

Answer 2

because it is on the tracks buddy.

Answer 3

does it work like the differential on a car. on a turn the inside whele spins less that then outer. this is only a guess im a car guy not a train man

Answer 4

Railroaders disqualified?  Then this must be some form of exam.  You state you've already received a "correct answer" at some point.  What then is the point of the question?

Is it some kind of ego enhancement?  I'm confused, but okay, I'll play along, and ask a question of you.  When speaking of an ABDW brake valve, name the three stages of preliminary quick service?  (Railroaders disqualified.)   Hint: Quick service is NOT a drive-in whorehouse.

By the by.  What was the correct answer for traversing the curve?

Answer 5

I believe the wheels have a slight taper to their profile.  Rather than being flat so the wheels roll completely square on the rail head, the taper allows the wheels to ride up or down on the head of the rail.  So, going around a curve, the inside wheel rides down, while the outside wheel rides up.  The difference allows the outside wheel to roll a slightly longer distance along the curve.

The taper allows a locomotive truck to slightly 'hunt' from side to side when rolling along a tangent (straight) track.  Axle snubbers have been added to trucks to dampen the hunting.

Hope that gets me 10 pts.

Answer 6

I take it you have never used London undergrounds central line at bank station where the curve is so sharp that a high pitched skweeling can be herd as the wheels slip on the rails.

Answer 7

Dang...I am disqualified... Actually one wheel does slip just a little...if you ever close to the tracks where there is a turn you will hear a high pitched squeal...that's wheel slippage... and it does wear the wheel...:) Some trackage has whats called rail lubricators ( some locomotives have flange lubricators..another story) which applies a combination of graphite and lube to the rail(just on the inside edge) to help reduce wear. This also helps the train through the turn...