Brunel Loading Gauge

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furnessvale

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Can anyone provide a link to a diagram of Brunel's broad gauge loading or structure gauges?

I have Googled. Plenty on the track gauge but nothing on the other gauges.
 
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MarkyT

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Can anyone provide a link to a diagram of Brunel's broad gauge loading or structure gauges?

I have Googled. Plenty on the track gauge but nothing on the other gauges.

I don't know precise details but loading gauge was not much if at all wider than typical standard gauge profiles of the period, or much taller. There was probably a little more clearance around and below the platform height, something exploited in some later GW standard gauge loco designs with room for bigger outside cylinders than were acceptable elsewhere. Box Tunnel is particularly deceiving in that the portals alone were designed with an oversize arch for visual impact whilst the rest of the tunnel between is smaller. It's notable that the floor of that tunnel has had to be lowered slightly in places to allow electrification. Other broad gauge tunnels and bridges of the same period were clearly not so large, see Sydney Gardens in Bath for instance - https://i.ytimg.com/vi/RprEb0rIlSE/maxresdefault.jpg
 

furnessvale

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I don't know precise details but loading gauge was not much if at all wider than typical standard gauge profiles of the period, or much taller. There was probably a little more clearance around and below the platform height, something exploited in some later GW standard gauge loco designs with room for bigger outside cylinders than were acceptable elsewhere. Box Tunnel is particularly deceiving in that the portals alone were designed with an oversize arch for visual impact whilst the rest of the tunnel between is smaller. It's notable that the floor of that tunnel has had to be lowered slightly in places to allow electrification. Other broad gauge tunnels and bridges of the same period were clearly not so large, see Sydney Gardens in Bath for instance - https://i.ytimg.com/vi/RprEb0rIlSE/maxresdefault.jpg

Yes, that is what I am trying to establish.

People insist on conflating his track gauge with loading gauge but I have found no evidence that loading gauge was any larger. If anything, it appears that the former LNWR gauge was larger.
 

jimm

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Yes, that is what I am trying to establish.

People insist on conflating his track gauge with loading gauge but I have found no evidence that loading gauge was any larger. If anything, it appears that the former LNWR gauge was larger.

Sorry, but is that the LNWR that was responsible for the notoriously tight clearances that still prevail north of Euston?

There was/is a fair amount of extra lateral clearance in GWR territory, especially above platform height, hence the GWR was able to build the 9ft 7in (2.92m) wide Super Saloons in the 1930s.

Even the much longer 165/166 Turbo units built for ex-GWR routes are 9ft 3in (2.81m) wide, while the 170s, derived from them, are 8ft 10in wide (2.69m).

At any rate, I can't say I'd fancy being a passenger on a 165/6 into Euston.
 

Kentish Paul

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If you look at early photos of broad gauge locos and stock most of the structure is inside the wheels. This was done for stability at speed. If the loading gauge was done in proportion to the track gauge then they would have had 3+3 seating with a wide aisle.
 

D869

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Not all broad gauge lines were equally broad. The Bristol & Gloucester was intended to be standard gauge before Brunel proposed building it to allow for broad gauge rails and it opened that way after a late decision to share the C&GWUR tracks from Standish to Gloucester that saved a considerable sum. The point of this preamble is to put the following quote from "The Bristol And Gloucester Railway" by C.G. Maggs in context:

As works were in quite an advanced state, the line was never fully broad gauge width. Wickwar and Staple Hill tunnels being only 26 ft wide, and underbridges the same between parapets. Clearances were small, as Great Western broad gauge coaches measured 11 ft 5 in. over the lower floorboards, which would have only left about 10 in. between the footboard and tunnel wall and 18 in. between footboards of passing coaches.

In the 1960s Roger Calvert proposed in his book "The Future of Britain's Railways" that Paddington should be the London terminus of a future Channel Tunnel route:

Great Western, The Wide Gauge Route
By adopting an International route into London for passengers and freight, the freight would be brought on to the former Broad Gauge route of the West London and so on to the old Great Western, which alone among British railways has an existing 9 ft. 8 in. wide load gauge extending not only to the West Country but also to Bristol, South Wales, Birmingham and Wolverhampton. Its potential is summed up by a quotation from the Railway Clearing House Coaching Arrangements book of 1888 which gives the available width (for rolling stock) as 11 ft. 6 in. (9 in. more than the modern American) and the height at centre as 15 ft. Of the railway pioneers only Brunel grasped the true potential and anticipated future requirements. Without alteration it might well be possible for most continental freight stock to work over the former broad gauge routes of the Western and London Midland Regions of British Railways, and some judicious sluing could lead to considerable extension of the International route. In 1952 the 'Mauzin Coach', a French vehicle carrying track testing equipment, was shipped to this country and ran extensive trials on the Western Region of BR (the only routes on which it could run freely) between Paddington and Frome and Hatton (Warwick).

I think "the height at centre as 15 ft" refers to the broad gauge headroom at rail underbridges and tunnels. The common width of 26 ft between bridge and viaduct parapets for double-track standard gauge has already been mentioned and the 'Blue Book' minimum is 25½ ft. I suggest without knowing for certain that the broad gauge figures are 30 ft for double track and 17 or 18 ft for single track.
.
 
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MarkyT

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There was/is a fair amount of extra lateral clearance in GWR territory, especially above platform height, hence the GWR was able to build the 9ft 7in (2.92m) wide Super Saloons in the 1930s.

Even the much longer 165/166 Turbo units built for ex-GWR routes are 9ft 3in (2.81m) wide, while the 170s, derived from them, are 8ft 10in wide (2.69m).

So it seems there were a few inches of extra lateral clearance, probably both above and below sole bar. I wonder if those super saloons would still fit today with presumably tighter stepping distances at modernised platforms. Apparently Turbos can run quite widely away from the former GWR with step-boards removed and they have done so over certain routes frequently for overhauls. In steam days I wonder if there were particularly large platform gaps to non-GW rolling stock (I'm thinking LMS coaches on holiday expresses, and of course BR Mk1s) compared to the earlier wider stock. Does anyone have any recollection of this?

If you look at early photos of broad gauge locos and stock most of the structure is inside the wheels. This was done for stability at speed. If the loading gauge was done in proportion to the track gauge then they would have had 3+3 seating with a wide aisle.

And once the decision to convert had been made, much subsequent traction and rolling stock was designed, from the outset, to be convertible. In the case of the locos, wheels were moved from the outside of the main frames to the inside on conversion.

Loading gauge varied quite widely in the early years right up until grouping. The GNR had more generous height than other parts of the LNER for example, which led to rebuilding of the early batches of Gresley A1s with a lower chimney, dome and cab roof in order to venture further north.
 

jimm

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So it seems there were a few inches of extra lateral clearance, probably both above and below sole bar. I wonder if those super saloons would still fit today with presumably tighter stepping distances at modernised platforms. Apparently Turbos can run quite widely away from the former GWR with step-boards removed and they have done so over certain routes frequently for overhauls. In steam days I wonder if there were particularly large platform gaps to non-GW rolling stock (I'm thinking LMS coaches on holiday expresses, and of course BR Mk1s) compared to the earlier wider stock. Does anyone have any recollection of this?

I wouldn't worry too much about below the solebar - things there have to comply with general standards, it's really about what you can do above it, hence the wide waistline of the 165/166 bodyshell and the Super Saloons.

Illustrating the lateral clearances, this is an original Brunel broad gauge bridge at Moreton-in-Marsh with a Class 180 - bodyshell width 8ft 11in (2.73) - passing underneath.

https://www.flickr.com/photos/willc2009/7035165355
 

Trog

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sorry, but is that the lnwr that was responsible for the notoriously tight clearances that still prevail north of euston?

lec1. W9&10.
Mln1. W8.
 
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furnessvale

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Brunel's broad loading gauge was slightly larger all round than the 'narrow', the structure gauge considerably so.

Not all broad gauge lines were equally broad, however. The Bristol & Gloucester was intended to be standard gauge before Brunel proposed constructing it to allow for broad gauge tracks and it opened that way after a late decision to share the C&GWUR tracks from Standish to Gloucester that saved a considerable sum. The point of this preamble is to put the following quote from "The Bristol And Gloucester Railway" by C.G. Maggs in context:



In the 1960s Roger Calvert proposed in his book "The Future of Britain's Railways' that Paddington should be the London terminus of a future Channel Tunnel route:



I think "the height at centre as 15 ft" refers to the broad gauge headroom at rail underbridges and tunnels. The common width of 26 ft between bridge and viaduct parapets for double-track standard gauge has already been mentioned and the 'Blue Book' minimum is 25½ ft. I suggest without knowing for certain that the broad gauge figures are 30 ft for double track and 17 or 18 ft for single track.
.

Thanks for that. It still leaves me puzzled as to where all this extra width and height has gone. 9' 6" containers to the west have to be on low wagons. Many bridges are being rebuilt for OHLE which in theory should fit. Even if clearances have been lost by years of tamping and realignments, it would surely be cheaper to get the track back where it came from, rather than rebuild structures, especially as reballasting and new track often accompanies electrification.
 

MarkyT

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Thanks for that. It still leaves me puzzled as to where all this extra width and height has gone. 9' 6" containers to the west have to be on low wagons. Many bridges are being rebuilt for OHLE which in theory should fit. Even if clearances have been lost by years of tamping and realignments, it would surely be cheaper to get the track back where it came from, rather than rebuild structures, especially as reballasting and new track often accompanies electrification.

What may have been specified for the original lines in the 1840s was not neccessarily replicated in the 1900s or 1930s when much route expansion, widening and structure and station rebuilding was carried out. Cant or superelevation of curves which eats headroom and side clearance was also unheard of on the Western until the 1960s. On the other hand the fairly straight alignment and generous clearances of the old GW allowed fairly painless upgrade of much of the route for 125MPH running in the 1970s.
 

edwin_m

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Transfer sheds were built at various break-of-gauge stations for transhipping goods between wagons. The ones I have seen pictures of do seem to have the entrance for one track wider than the other, such as this one:

https://en.wikipedia.org/wiki/Exete...:2008_at_Exeter_St_Davids_-_transfer_shed.jpg

Not all GW lines were built to broad gauge of course, and where they were the extra space has no doubt been "robbed" in some places since 1892 or the track slewed towards one side. The issue with containers is not the overall height or width but the fact that these dimensions must be available in the top corners of the gauge, whereas traditional gauges have a curved profile at the top. Thus a modern container train may actually violate even Brunel's loading gauge.

Platform offsets are also pretty much the same as anywhere else on Network Rail, meaning maximum widths below solebar are also the same, and even if nothing else does this would make it impossible to run Continental stock on ex-GW lines.
 

MarkyT

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This is an interesting image, showing dual gauge track in the transfer shed at Didcot Railway Centre.

https://www.flickr.com/photos/[email protected]/4960774027

If a standard gauge wagon can berth against the loading platfrom with sufficient clearance then this suggests that a broad gauge vehicle that also reaches sufficiently close to the platform edge would be considerably wider overall at solebar level. Otherwise there would be a huge gap to step across.
 

furnessvale

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This is an interesting image, showing dual gauge track in the transfer shed at Didcot Railway Centre.

https://www.flickr.com/photos/[email protected]/4960774027

If a standard gauge wagon can berth against the loading platfrom with sufficient clearance then this suggests that a broad gauge vehicle that also reaches sufficiently close to the platform edge would be considerably wider overall at solebar level. Otherwise there would be a huge gap to step across.

Or one or other of the wagons could use a bridge plate.
 

jimm

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lec1. W9&10.
Mln1. W8.

I was referring to the lateral clearances, as it is perfectly obvious looking at the picture of that bridge I linked to that the extra clearance on broad gauge compared with other Victorian-era bridges was fundamentally lateral, not vertical. Container gauge clearances are essentially about increased shoulder and vertical height, not extra width. And the London & Birmingham/LNWR was not built to anything remotely like W10 gauge, was it? What you see there today is the result of 1960s and more recent clearance work.

Thanks for that. It still leaves me puzzled as to where all this extra width and height has gone. 9' 6" containers to the west have to be on low wagons. Many bridges are being rebuilt for OHLE which in theory should fit. Even if clearances have been lost by years of tamping and realignments, it would surely be cheaper to get the track back where it came from, rather than rebuild structures, especially as reballasting and new track often accompanies electrification.

What extra height? You might just about squeeze 25kv under the arch of the bridge in the picture I linked to but there are three others just a few miles away from it where you will never get 25kv under. And that's why a series of Brunel bridges have been demolished along the GWML for electrification, or track was lowered under them - there was precious little more vertical clearance on broad gauge than standard gauge lines. Visionary that he was, Brunel didn't know about 25kv or 9ft 6in shipping containers on standard platform wagons.

But the width is still there, hence the bodyshells of the Turbos. When they move west, pretty much the only issue to be resolved gauge-wise will be to ensure the stepping plates don't foul platforms and ensuring they fit through bridges, etc of recent vintage. If someone had asked, Hitachi could have built a wider 800/801 for the GW area, but as the trains are intended for other areas as well, they are to a standard size.
 

furnessvale

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I read all the responses and understand that there is some width advantage.

I originally asked if anyone had a link to an actual loading or structure gauge for broad gauge so I could make comparisons with other gauges.

My inability to find one and the lack of the collective might of this forum finding one, leads me to think one does not exist.
 

jimm

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If you mean online, then no, doesn't look like there is a diagram. There might be one in a book somewhere, but I can't find one in any of the Brunel-related books I have.

The best I can manage is a line from here

http://mike.da2c.org/igg/rail/2-track/02track3.htm

The former GWR broad gauge lines have the most generous clearances on BR with thirteen foot six inches (4.1m) vertical clearance and nine foot eight inches (2.9m) width at the widest point
 

furnessvale

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If you mean online, then no, doesn't look like there is a diagram. There might be one in a book somewhere, but I can't find one in any of the Brunel-related books I have.

The best I can manage is a line from here

http://mike.da2c.org/igg/rail/2-track/02track3.htm

Thanks for that. The height seems fairly standard. 13' 6" was standard LNWR.

The width is more at 9' 8" but not as much as I would have expected. Without digging out some diagrams I believe LNWR was 9' 3" over handles. A gain of 2.5" each side is not much.
 

MarkyT

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Following on from the Didcot transfer shed, this photo is also informative:
https://en.wikipedia.org/wiki/List_...es#/media/File:GWR_Dragon_at_Taunton_1892.jpg
This one shows an Iron Duke class locomotive at Taunton in 1892 hauling passenger carriages that appear quite narrow in the body, but with very wide step-boards at and below sole bar level. Presumably these coaches were designed to be convertible by swapping bogies and modifying the stepboards which would bring their sides closer to platforms. Earlier broad gauge carriages and wagons seem to be more straight sided and wider overall. Note the dual gauge track as by this time much of the network was already dual gauge to facilitate the imminent final changeover.
--- old post above --- --- new post below ---
Definitely no 'tumblehome' to solebar
http://www.broadgauge.co.uk/library..._gas_works/hollicombe_gas_works_01_xlarge.jpg
--- old post above --- --- new post below ---
And another 'last broad gauge train' shot at Swindon. This time with the first car a narrower 'convertible' van leading a train of full width broad gauge passenger coaches no doubt very shortly destined for the scrapline along with the non-convertible locomotive.

http://www.swindonviewpoint.com/sit... is either scrapped or converted May 1892.jpg
 

Trog

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I was referring to the lateral clearances, as it is perfectly obvious looking at the picture of that bridge I linked to that the extra clearance on broad gauge compared with other Victorian-era bridges was fundamentally lateral, not vertical. Container gauge clearances are essentially about increased shoulder and vertical height, not extra width. And the London & Birmingham/LNWR was not built to anything remotely like W10 gauge, was it? What you see there today is the result of 1960s and more recent clearance work.

Before you get so shrill may I remind you of the words "still prevail" in your first post, hence why I pointed out that the WCML route is actually wider at height where the width is most useful than the GWR. Those clearances include through the L&B built tunnels, and were achieved without doing large scale lowering. Which is just as well as most of the tunnels have inverts, and not a lot of ballast.
 

edwin_m

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Before you get so shrill may I remind you of the words "still prevail" in your first post, hence why I pointed out that the WCML route is actually wider at height where the width is most useful than the GWR. Those clearances include through the L&B built tunnels, and were achieved without doing large scale lowering. Which is just as well as most of the tunnels have inverts, and not a lot of ballast.

Is this comment not referring to the track spacing? I believe the LNWR didn't provide the normal "ten foot" when quadrupling and this causes problems for WCML maintenance to this day.
 

HowardGWR

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I had a brief look for the article I am about to reference but have not been able to locate it.

I believe it was published in the GWS magazine 'Great Western Echo' by a member with the amazing name of Amyas Crump.

Amyas displayed the Brunel loading gauge 'proving' that the body gauge limits were a function of taking the 'Stephenson' gauge and somewhere using the constant pi as a factor. 7ft 0 and 1'4" for the track is of course just a half extra.
It was a very interesting article, so perhaps someone can recall its reference.
 
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