
Physicist Richard Feynman explains how a train stays on the tracks. - amichail
http://www.youtube.com/watch?v=y7h4OtFDnYE
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jhayes
This clip (and the others posted by 'ChristopherJSykes') are from the BBC show
"Fun to Imagine". Been a few months, but I remember the 'Magnets (and 'Why?'
questions...)' segment being particularly worthwhile if you're looking for
good bang-for-buck timewise.

Incidentally, the guy releasing this also directed it.

Also in case you prefer text: <http://varatek.com/scott/feynman_problems.html>

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arketyp
Wow, neat. I'm not sure I should attribute all my amazement to Feynman, but it
sure is lovely hearing that man explain things.

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Luc
So now all I need to do is figure out what determines the angle of the taper
on the wheels...

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pbhj
The difference between the circumferences would have to be such that the train
could round the sharpest bend on the track.

That should approximate to a maximum angular change (in direction of travel)
per metre:

angle per metre = tan( 2 PI (R-r) / inner track gauge ) x 2 PI r

where R is the largest contact circumference of the wheel and r the smallest.

?

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TrevorJ
What I don't get is how the train rounds a variety of curve radii. How do they
control the part of the wheel that is riding the rail precisely enough to
allow the train to turn at differing angles depending on the radius of the
curve?

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TrevorJ
Hmm, sorry for the double post, not sure what happened there.

