How trains make turns without differentials

You know how the car differential works, right? Well, have you ever wondered how trains take corners, with their wheels connected by solid steel axles? In this clip from the BBC series Fun to Imagine, America’s coolest nuclear physicist and frigideira percussionist Richard Feynman leaves the world of quantum electrodynamics and samba to explain the simple brilliance of train wheels.



GuardDuck_Quick draw anger management

It's amazing how something so apparently simple could be just *that* much more complex. I've always known that train wheels are coned and thought that the only purpose was to cut down of contact patch with the see, a train's wheels are supposed to only contact the rails on the very inner edges of the rails to cut down on rolling resistance. I had assumed that the differential issue was covered by simple slippage and low-radius turns.

The problem I see is what happens if you have turns of a different radius? Wouldn't you then need a different degree of coning of the wheel for each different radius? Maybe he's talking out of his ass and *I'm* the one who's right!!! Wouldn't be the first time...

Time to get out the slip stick and prove this new theory out...I gots to know!!