Rail Tracks

[ossian]

For years now rail tracks have been welded to produce a smooth, continuous rail with no gaps like the old tracks had, hence the lack of the clickety clickety sound. What happens on a very hot day? If you consider a 30 km. stretch of track the expansion of such a length of steel rail must run to quite a few hundred metres. Is provision made for this expansion at either end of thbe track? I know I should have checked out the coeff. of linear expansion to determine the exact length of this expansion but a few hundred metres should be close.

Many Thanks,

Stewart

[bazwillrun]

http://en.wikipedia.o...ontinuous_welded_rail

[Teddio]

The rails are in tension so when the temperature increases the tension in the rails decreases. There is therefore no tendency for the rail to expand.

[nescio]

If you had bothered to check the coefficient of expansion, you would have found that for say, a 30 degree rise in temperature, the expansion in a 30km length of track would be no more than about 10 metres and certainly nowhere near " a few hundred metres".

[pdq1]

///One mile is 5280 feet so one mile is 12 5280 = 63360 inches. One inch of steel will expand 0.00000645 inches for every degree Fahrenheit increase in temperature so 63360 inches will expand

63360 0.00000645 = 0.408672 inches per degree.
A 40 degree increase in temperature will result in an expansion of

40 0.408672 = 16.35 inches per mile.

[jake-the-peg]

///One mile is 5280 feet so one mile is 12 5280 = 63360 inches. One inch of steel will expand 0.00000645 inches for every degree Fahrenheit increase in temperature so 63360 inches will expand ///

And people wonder why we moved to proper metric units?

How many groats per foot do they cost?

[pdq1]

Thank goodness miles are still in fashion.

[xud]

If metric was an American invention, you can be pretty sure they would want the whole world to be the same.