British Railway Track

[joe.s-b]

Why it the track 8 foot 4 and a half in UK

[Jackdaw33]

It isn't. It's 4 ft 8½ inches.

[Baldric]

Approximately Fifty-five per cent of the world's railways use 4 ft 8 1⁄2 in (1,435 mm) standard gauge

https://en.wikipedia.org/wiki/Track_gauge

[joe.s-b]

Sorry. I meant 4 foot 8 of course. But why?

[Jackdaw33]

Historical reasons. Stephenson's first trains ran on this gauge.

[Jonathan-Joe]

National Rail has adopted the international standard 1435 mm.
https://en.wikipedia.org/wiki/Track_gauge

[Old_Geezer]

http://www.snopes.com/history/american/gauge.asp
Any use ?

[jno]

the GWR started with a 7 foot gauge but it didn't catch on

https://en.wikipedia.org/wiki/Great_Western_Railway#Brunel.27s_7-foot_gauge_and_the_.22gauge_war.22

[atalanta]

Ever been on a train which had to change gauge ? I have. At Brest-Litovsk, where a whole load of beefy chaps spent 3 hours hammering the train - presumably taking the carriage off one lot of wheels and transferring it to another lot. I couldn't help thinking, through the headache caused by the din, that it would have been vastly simpler to get us out of one train and put us in another. Anyone know why they don't ?

[mikey4444]

I have it in my memory that Brunel wanted a wider gauge, as it would be more stable. But he was put off the idea because of the much larger cost of all that track laying, bridges and tunnels that a larger track would entail.

But there are better experts on here than me !

[Jackdaw33]

The 7' gauge lasted till the 1890's but the increase in traffic and the need to change gauges made impractical. As most of the network was standard gauge it was cheaper to convert from broad gauge.

[mikey4444]

There....I knew somebody would know !

[joe.s-b]

Thanks all but what is the engineering or technical reason for the current gauge?

[mushroom25]

the reason for the unusual figure is lost in the mists of time. but probably the best trivial reason could be that road carts traditionally had wheels set 5'0" apart, measured across the outside edges (so that a good sized horse fitted between the drawspars). railways work best if the wheel flanges are on the insides of wheels, so 5'0" - 2"x2 = 4'8", which was the gauge used on many mine tramways in the north of england. george stephenson added half an inch to reduce binding on sharp curves and hey-presto, 4'8 and a half.....

[joe.s-b]

Thanks Mushroom. That makes sense so all is now understood.

[ToraToraTora]

it was on QI, it goes back to Roman carts believe it or not.