Are you sure you're not getting your 8ft 4½in mixed up with 4ft 8½in, Chris

There's broad gauge and there's very broad gauge!  One thing mentioned earlier was loading
gauge, not sure why Britain ended up with a  smaller loading gauge on standard track compared
with Europe. And I think this led to the scale differences in N gauge , 1/148 UK, 1/160 Europe.
If I'm wrong on last point no doubt I'll be shot down in flames !

Could possibly be from either the navvies that were used to building structures for the canals, or just that as the old colliery wagon ways had a restrictive loading gauge it wasn't thought necessary to make it any bigger as the railways were originally for moving goods and not passengers. And most of the goods in the early Victorian days were fairly small items, coal or stone?

I believe the loading gauge was literally down to the fact we don't have the room the Europeans have
As a consequence tunnel bores (be it railway or canal) were always very tight - hence us not being able to use double decker trains, apart from the ones used on the Southern Region multiple units where the legs of the folks on the upper deck dangled into the spare space between those on the lower deck.
Odd really, when you consider 1/160 is smaller than 1/148

Quote from: newportnobby on January 09, 2015, 11:02:52 AM
Odd really, when you consider 1/160 is smaller than 1/148

That's the point: In reality our rolling stock is smaller, so we need a bigger model of it to squeeze a decent size motor and other gubbins in.

The chimney on the Rocket (Stephenson's one, not the space shuttle) was too tall to go under most bridges, including the one at Rainhill.  I'm not sure whether they decided it worked OK with a shorter chimney and built the bridges accordingly, or the bridges were there first and Stephenson had to trim the chimney down once he'd won the competition. 

A similar thing occurred when the a Leicester & Swannington railway opened, they found the chimney on the loco(a Stephenson's product, as well as the L&S having Robert Stephenson as engineer) fouled the roof of Glenfield Tunnel(in 1832 it was apparently the longest rail tunnel in the world). Glenfield tunnel did have a notoriously narrow bore though, passenger coaches had to be specially made for it, and locos had to have cut down chimneys and narrowed & cut down cabs to work through to West Bridge, and in BR days any railtours had to be formed of brake vans as MK1 stock was too big...

I believe the track gauge goes back to the wheel set from a Roman chariot and a single tunnel is the width of two horses pulling the chariot.
Steve.

Quote from: xm607 on January 09, 2015, 03:20:35 PM
I believe the track gauge goes back to the wheel set from a Roman chariot and a single tunnel is the width of two horses pulling the chariot.
Steve.

I'm sorry, but that's utter nonsense! So 2000 years after the Romans used wooden wagonways, just one insignificant colliery in the northeast of England decided that 'As the Romans used 4 foot 8.5 inches as the track gauge on their wagonways that nobody knew existed until the late 20th century we should do that same, even though we're blissfully unaware of this historical possibility until many years after we're going to die.'
More like the collieries in the northeast all had a broadly similar track gauge, but as the colliery Stephenson was engineer at had 4 foot 8.5 inches, that's what he was used to working with and that what all the railways he was involved with ended up using. Besides, Roman chariots were horse drawn and had only 2 wheels, and didn't need to be guided down a road with ruts or rails, but a coal wagon at a 19th century colliery would have had 4 wheels with a rigid wheelbase and as such had no means of steering.

The early waggonways evolved from traditional cart tracks, and probably for some time during this process the wagons would have been able to continue their journeys away without rails.  That's one reason why a lot of them had flanged rails and non-flanged wheels. 

Quote from: Wingman mothergoose on January 09, 2015, 03:49:26 PM

Quote from: xm607 on January 09, 2015, 03:20:35 PM
I believe the track gauge goes back to the wheel set from a Roman chariot and a single tunnel is the width of two horses pulling the chariot.
Steve.

I'm sorry, but that's utter nonsense! So 2000 years after the Romans used wooden wagonways, just one insignificant colliery in the northeast of England decided that 'As the Romans used 4 foot 8.5 inches as the track gauge on their wagonways that nobody knew existed until the late 20th century we should do that same, even though we're blissfully unaware of this historical possibility until many years after we're going to die.'
More like the collieries in the northeast all had a broadly similar track gauge, but as the colliery Stephenson was engineer at had 4 foot 8.5 inches, that's what he was used to working with and that what all the railways he was involved with ended up using. Besides, Roman chariots were horse drawn and had only 2 wheels, and didn't need to be guided down a road with ruts or rails, but a coal wagon at a 19th century colliery would have had 4 wheels with a rigid wheelbase and as such had no means of steering.

Its the width between the chariots two wheels and I know they did not run on tracks or rails, this came from the reason NASA gave for the space shuttle solid rocket boosters size and construction after the Challenger disaster, why they could not be made in one piece, because of transportation for refurbishment through railroad tunnels on a system based on ancient dimensions.
Steve.

Quote from: xm607 on January 09, 2015, 05:03:51 PM
Its the width between the chariots two wheels and I know they did not run on tracks or rails, this came from the reason NASA gave for the space shuttle solid rocket boosters size and construction after the Challenger disaster, why they could not be made in one piece, because of transportation for refurbishment through railroad tunnels on a system based on ancient dimensions.
Steve.

That's interesting - do you know if this is documented anywhere Steve?

Quote from: austinbob on January 09, 2015, 05:14:33 PM

Quote from: xm607 on January 09, 2015, 05:03:51 PM
Its the width between the chariots two wheels and I know they did not run on tracks or rails, this came from the reason NASA gave for the space shuttle solid rocket boosters size and construction after the Challenger disaster, why they could not be made in one piece, because of transportation for refurbishment through railroad tunnels on a system based on ancient dimensions.
Steve.

That's interesting - do you know if this is documented anywhere Steve?

Why yes, on the previous page of this thread, and for the tl;dr crowd here (disclaimer: not everything you read on the internet is necessarily true).

The chariot thing is a myth. Yes the distance between chariot wheels nay have np been roughly 5 feet, but I wasn't aware Ancient Rome used the Imperial system of measurement, more than likely it was a rough guess due to the need to fit a horse in the traces between the two wheels and it could vary a fair amount from chariot to chariot. If two horses were used then the wheels would be wider apart than 4 foot 8.5 inches! Also the Romans didn't invent the chariot, they were around for hundreds of years(or longer) before Rome was even founded. The NASA thing is true though don't really know about 'ancient dimensions' though, as most US railroads were built to fairly generous proportions.
It's only chance that the 'standard gauge' of the railways ended up as 4 foot 8.5 inches, if Stephenson had worked at a different colliery it could just as easily have been 3 feet or 6 feet or anything else.

I've just found the real reason for 4ft 8.5 inch guage track:-

Because its the mean distance between the neck and ankles of damsels in distress.