gauge

[387star]

How do Eurostars manage to operate on our narrow and European wide gauge?

Plus will the new High Speed line be built to wide guage

I heard Great Western is wider how does that work

 

[ainsworth74]

Eurostars are built to fit the British loading gauge. I think its worth pointing out that the space between the rails on the continent and GB remains the same (4 ft 8 1⁄2 inch) its the space above the railhead that's different.

HS2 will be built to the full European high speed loading gauge I belive that it's called something like GC (see here for some more info).

The GWML was originally built as a two track broad gauge railway, that means the gap between the rails was 7 ft and 1⁄4 inch whilst standard gauge is only 4 ft 8 1⁄2 inch. So when the GWML was re-gauged into standard gauge you automatically gained more space around the tracks. I think most of this has now been lost due to realignment of the track (to allow higher speed) and with quadrupling certain sections of the GWML.

 

[The Barlow Boy]

Right. First of all the word is gauge. Now, to answer your questions.........
1
The gauge to which you are referring to is the running gauge. This - with the exception of Ireland, Portugal, the Spanish "classic" lines and Finland is the same throughout Europe (I haven't included Russia) which is 4' 8.5" in black and white, 1.435mm in colour. This is known as standard gauge. If narrower it's narrow gauge, if wider it's broad gauge. In mentioning our "narrow gauge" you're getting confused with the loading guage which is the dimensions that a rail vehicle is allowed to be. Britain's is the smallest This can be best seen at St. Pancras when a Eurostar train is sat in the platform where there's a fair gap between the train and the platform. If you can get hold of a picture of the German train that was in there last October(?) you'll see that it filled the platform edge completely.

2
Don't know but a sensible (what, in this country?) decision would see it being built - if built - to the UIC gauge (that's the generous so-called Continental gauge)

3
The original London and Bristol railway that became the Great Western was originaly built to a 7' running gauge. This was reflected in the somewhat more generous loading gauge. The entire Great Western was converted to standard gauge late in the 19th century - over one weekend! (a lot of preliminary work had been carried out beforehand though). The legacy of this can be seen in the greater distance between the running lines over former Great Western territory.

 

[LE Greys]

I think the OP is confusing rail gauge (the width between the rails) with loading gauge (the size of rolling stock). The rail gauge in Britain and throughout most of continental Europe is 4 ft 8½ in (or 1,435 mm) and Eurostars run fine on that gauge. However, the loading gauge is bigger in Europe. If you ever go to Paris, look at a Eurostar next to a TGV, and you will see that the TGV is visibly bigger. For exact descriptions of loading gauge, click on the link below.

The GWR once had a rail gauge of 7 ft ¼ in, but the loading gauge was not all that much bigger than standard gauge (wider, but no higher). To cope with that, many lines had a third rail laid, allowing dual-gauge operation. In some places, such as Ireland (5 ft 3 in) and Spain (5 ft 6 in on older lines), the gauge is still broad. Some cross-border trains from France to Spain have variable gauge stock. Others (such as Poland-Ukraine) jack the stock up and change the bogies. Again, full explanation below.

http://en.wikipedia.org/wiki/Loading_gauge
http://en.wikipedia.org/wiki/Variable_gauge
http://en.wikipedia.org/wiki/Bogie_exchange

 

[jopsuk]

I think HS2 is specified to be built to UIC GB+ or GC loading gauge (the difference is height)

 

[Sapphire Blue]

Why such a (seemingly) random figure of 4'8 1/2"?

 

[gordonthemoron]

are TGVs narrower than ICEs? or is that just an optical illusion due to their increased height?
--- old post above --- --- new post below ---

Why such a (seemingly) random figure of 4'8 1/2"?

originates I believe with coal mines in NE england

 

[jopsuk]

you'll find plenty of utter bull about why exactly it is 4' 8½", with the truth being that there's no special reason, it's just approximately the gauge at the coal mines local to Stephenson.

 

[krus_aragon]

Why such a (seemingly) random figure of 4'8 1/2"?

That's what was already used on the horse-drawn tramways where George Stephenson learnt his trade, so he just stuck with that gauge on all other railways he built.

Even the broad gauge's inventor, Brunel, chose the 'narrow' (4'8 1/2") gauge for the Taff Vale railway for which he its engineer in the 1840s. This was primarily a mineral railway, like the Stockport and Darlington, and Brunel's broad gauge was designed for comfort and speed.

 

[pendolino]

1.435mm in colour.

With the tracks that close together, you'd think the trains would fall over

 

[Bomber]

I believe that the gauge goes back a lot further, it was the approximate distance between the wheels of the carts and chariots that the Roman brought when they invaded this country. When they left our carts etc were then built so that the wheels fitted into the ruts left in the Roman built roads, other widths would not work as either one or the other wheel dropped into the rut and loads would slip off as the cart tipped.

 

[gordonthemoron]

if the Barlow Boy was referring to the german numeric notation, 1.435mm is correct, i.e. 1435mm

Edit: I think Bomber is correct

 

[Bomber]

Further searching comes up with, these carts etc were usually hauled by 2 horses, and the width needed to be sufficient so that where the horses walked/galloped did not cut up the ground that the wheels ran on, if they did then you got a very rough ride as opposed to just a rough ride......:grin:

 

[jrhilton]

are TGVs narrower than ICEs? or is that just an optical illusion due to their increased height?

I think TGVs (the latest TGV POS) are slightly narrower than ICE3s, by about 5 cm. Both are around the 2.9m wide mark.

With regard to the GWML and broad gauge, I was under the impression that the actual broad-gauge carriages were physically at their widest point, really no wider than modern UK stock at around 2.8m? Can someone confirm this?

 

[Ploughman]

Why such a (seemingly) random figure of 4'8 1/2"?

Or even more random
Why did Brunel choose 7ft and a 1/4 inch?

 

[swt_passenger]

Eurostars are built to fit the British loading gauge. I think its worth pointing out that the space between the rails on the continent and GB remains the same (4 ft 8 1⁄2 inch) its the space above the railhead that's different.

When Eurostars used Waterloo they coped with different platform stepping distance/height by having steps that extend depending on the platfom position.

Of course St Pancras meets modern European standards (760mm), but various other platform heights are found all over Europe anyway, I think the Paris and Brussels platforms are also different...

 

[gordonthemoron]

Wasn't Brunel part french?

7ft and a 1/4 inch is 2.14 metres if that's any clue

 

[Sapphire Blue]

Or was it to allow the trains to be built 7 ft exactly to allow a 1/4 inch tolerance?

 

[starrymarkb]

I think TGVs (the latest TGV POS) are slightly narrower than ICE3s, by about 5 cm. Both are around the 2.9m wide mark.

With regard to the GWML and broad gauge, I was under the impression that the actual broad-gauge carriages were physically at their widest point, really no wider than modern UK stock at around 2.8m? Can someone confirm this?

Older ICEs are widebodied though - ICE3 is built to UIC

 

[LE Greys]

Or even more random
Why did Brunel choose 7ft and a 1/4 inch?

56½in X 1.5 = 84¾ in

It's only ½ in narrower than exactly 1.5X standard gauge. I don't think it had anything to do with metric, I have never seen a Brunel drawing marked up in anything other than feet and inches in any museum anywhere. Another reason might be that the ½ in on standard gauge and the ¼ in on broad gauge was a tolerance allowed for the wheel flanges.

Now another, was there ever any trackside equipment built to 1 ft 3¾ in? That's the width between the opposite running rails for dual gauge.

 

[ChrisCooper]

The extra 1/2 in and 1/4 in in standard and broad gauge were both added to improve ride and cornering. Broad gauge was therefore originally the simple 7ft. 4ft 8in standard gauge was just what George Stephenson favoured. Traditionally guage was between 4 and 5ft, and wheels on carts were similar spacing as it's the sort of width needed to fit a horse between the shafts.

 

[Wyvern]

Now another, was there ever any trackside equipment built to 1 ft 3¾ in? That's the width between the opposite running rails for dual gauge.

There is Minimum Gauge at 1 ft 3 in

 

[The Barlow Boy]

With the tracks that close together, you'd think the trains would fall over

Well spotted Wilson.

 

[jopsuk]

I believe that the gauge goes back a lot further, it was the approximate distance between the wheels of the carts and chariots that the Roman brought when they invaded this country. When they left our carts etc were then built so that the wheels fitted into the ruts left in the Roman built roads, other widths would not work as either one or the other wheel dropped into the rut and loads would slip off as the cart tipped.

I'm pretty sure this answer would set off the klaxon on QI

 

[Class41]

The current class 165 and 166 Thames units were built to a wider loading gauge than standard to benefit from the larger clearances on the GWML.

Some stock on the Southern had to be built to a narrow loading gauge to accommodate restricted clearances on the Hastings line, e.g. 201s and 33/2 class locos.

 

[Bald Rick]

The current class 165 and 166 Thames units were built to a wider loading gauge than standard to benefit from the larger clearances on the GWML.

Urban myth I'm afraid. If this was the case they wouldn't fit on various railways off the GW they operate on, some of which were built after the last broad gauge train ran.

One Quite Interesting fact, maths fans: as near as makes no difference...
Standard gauge is Pi/2 yards, Broad gauge is Pi-1 metres.

 

[krus_aragon]

One Quite Interesting fact, maths fans: as near as makes no difference...
Standard gauge is Pi/2 yards, Broad gauge is Pi-1 metres.

That might be of some relevance to Brunel's customed designed gauge. Sadly I know too little of its history to say anything more.

I don't suppose anyone would be able to point me to some good reading material on Brunel's development of his gauge, preferably dealing with the nitty gritty engineering?

 

[ChrisCooper]

165s and 166s are built a little bigger than normal stock as they are almost the maximum 2.82m width (2.81 to be precise) yet a good 2m longer than stock normally built to that width (normally 65ft or just over 20m). Normally as the coaches get longer they get narrower (153s which at 23.3m are AFAIK the longest are just 2.7m wide). This doesn't mean they are restricted to just the GWR (and the GCR which was built to continental gauge), but they might have problems on some routes.

 

[Trog]

(and the GCR which was built to continental gauge).

Urban myth.

Berne Gauge standard set 1912.

Great Central London Extension built 1899.

 

[tbtc]

165s and 166s are built a little bigger than normal stock as they are almost the maximum 2.82m width (2.81 to be precise) yet a good 2m longer than stock normally built to that width (normally 65ft or just over 20m). Normally as the coaches get longer they get narrower (153s which at 23.3m are AFAIK the longest are just 2.7m wide). This doesn't mean they are restricted to just the GWR (and the GCR which was built to continental gauge), but they might have problems on some routes.

I know there's talk of 165/166s being cascaded to Avon/ Devon/ Cornwall when the Thames Valley electrification takes place (albeit not loads of them, as the branches won't be wired), but will it be worth doing clearances on branches (if it is needed)?