Imaginary Locomotives

[goldfish]

2 hours ago, JimC said:

Once there are high platforms (how early did they come in?) expansion of the gauge is pretty much stuffed. 

A B.O.T. Order of 1875 required a standard platform height of 2ft 6in, before that presumably platforms were much lower.

[Jeremy Cumberland]

3 hours ago, Compound2632 said:

 

So they moved to standard gauge - which they need not have done, having pretty well a clean slate. They could perfectly well have gone for, say, 5' 3" gauge. 

I wonder if they had a mind on the export market. Look what we could build for your railways.

 

Regarding horses, I don't think the width of the horse comes into it. Horses were widely-used on narrow-gauge mine and quarry railways, and I imagine that some of these date from the late 1700s. However, such narrow vehicles would have been no good for road use because of the state of the roads. Large diameter wheels were needed because of the uneven road surface, This in turn meant a high floor, and a wide wheelbase was needed for stability. Tramways had smooth rails or plates, so small wheels were fine, and there would not have been the same stability issues in any case, at least, not until you wanted to put a large boiler on your wagon.

[tythatguy1312]

56 minutes ago, Compound2632 said:

 

Not necessarily. Japan is an archipelago with no very high prospect of creating a fixed link to continental Asia. So there was absolutely no external constraining factor on the choice of gauge for a high speed passenger network - they could have gone down the route of a maglev monorail.

that seems to have been a big thing for islands & archipelagos. The Ponta Degalda harbour railway is a prime example, using 7ft gauge on an isolated network into the 1960's.

[john new]

2 hours ago, Jeremy C said:

I wonder if they had a mind on the export market. Look what we could build for your railways.

 

Regarding horses, I don't think the width of the horse comes into it. Horses were widely-used on narrow-gauge mine and quarry railways, and I imagine that some of these date from the late 1700s. However, such narrow vehicles would have been no good for road use because of the state of the roads. Large diameter wheels were needed because of the uneven road surface, This in turn meant a high floor, and a wide wheelbase was needed for stability. Tramways had smooth rails or plates, so small wheels were fine, and there would not have been the same stability issues in any case, at least, not until you wanted to put a large boiler on your wagon.

I quoted horses backsides because the majority of carts were sized to a horse. The waggons would have utilised existing skills and knowledge.

 

I concur horses on narrow gauges, as you mention, not unknown.

[Flying Fox 34F]

On 21/11/2022 at 18:26, Compound2632 said:

 

The L&B Manning Wardles were 6' 6" or thereabouts over the outside cylinders; a 3 ft gauge equivalent would have to be 7' 6" wide. How wide over cylinders were the County Donegal Naysmith Wilsons? (Which were also outside-framed and outside-cylindered.) 

The Donegal 2-6-4t’s were 8 feet wide.  33 feet long and 11 feet tall.  
 

As for the 5’ 3”, CIE had coaches 10 foot 6 inch wide.  Looking carefully at locomotive design in Ireland, the wider gauge allowed for shorter locomotives.  The firebox and grate area would be shorter than a British locomotive.  There were big locos, but most were smaller than their equivalents in Britain.

 

Paul

[Compound2632]

3 minutes ago, Flying Fox 34F said:

The Donegal 2-6-4t’s were 8 feet wide.  33 feet long and 11 feet tall.  

 

As wide as many standard gauge tank engines.

[Flying Fox 34F]

I have seen it written that the Donegal tanks were a similar size to a GWR Small Praire.

They also had 4 foot diameter driving wheels and could achieve a fairly high speed.

 

Paul

[DavidB-AU]

Here's the Queensland Rail loading gauge diagram. 2850mm maximum width is 9'4" on 3'6" gauge and modern coal hoppers are built to the absolute limits of the loading gauge. Container flat wagons are more typically around 2450 mm  (7'11").

 

 

But to show what really can be done on 5'3" gauge, the South Australian Railways 500 class built by Armstrong Whitworth was massive. Although "only" 9'7" wide, they weighed a massive 222t and had a TE of 51,000 lb.

 

 

 

[tythatguy1312]

16 hours ago, DavidB-AU said:

Here's the Queensland Rail loading gauge diagram. 2850mm maximum width is 9'4" on 3'6" gauge and modern coal hoppers are built to the absolute limits of the loading gauge. Container flat wagons are more typically around 2450 mm  (7'11").

 

 

But to show what really can be done on 5'3" gauge, the South Australian Railways 500 class built by Armstrong Whitworth was massive. Although "only" 9'7" wide, they weighed a massive 222t and had a TE of 51,000 lb.

 

 

 

Terrified to imagine what a 7ft gauge 4-8-2 would've looked like in the best way.

[JimC]

17 minutes ago, tythatguy1312 said:

Terrified to imagine what a 7ft gauge 4-8-2 would've looked like in the best way.

I've tried thinking about what a big say 1930s British 7ft gauge locomotive would look like, and its a surprisingly difficult challenge. I gave up before I got very far because it rapidly became evident that it would have to be utterly different from anything that was built. The big issues were weight and loading gauge.
Firstly, there's no more room for outside cylinders than there is on the narrow gauge, so the sort of huge cylinders seen on US types and even metre gauge types are impractical. It leads one towards a 4 cylinder compound, because small outside cylinders are mandated, hence high pressure ones, but there's plenty of room for truly enormous low pressure cylinders between the frames, so the division between high and low pressure can be much better managed than  is normally the case.
And now the boiler. Yippee, I thought, plenty of room for a really big efficient boiler and a wide grate between the frames. We can have the best aspects of wide and narrow fireboxes.  And so we can, except I'm not sure what that would look like. But hang on: the eaves are rather low on the broad gauge. My huge boiler probably can't have a belpaire firebox unless we back it down a bit in size. Unless it has a round top box the firebox corners are a big limitation. But a bigger issue is weight. Lets say I have a 22 ton axle weight limit. My boiler just can't be much bigger in diameter than a King or Duchess boiler, because what's going to carry the weight? Driving wheels are close to touching on those anyway, can't fit another pair in under the shorter fatter boiler. 
And so it goes on. I decided that I couldn't sketch up something reasonably credible without a far greater understanding of steam locomotive design than I possess. Starting from standard gauge deigns just didn't work for me.

[rodent279]

9 minutes ago, JimC said:

I've tried thinking about what a big say 1930s British 7ft gauge locomotive would look like, and its a surprisingly difficult challenge. I gave up before I got very far because it rapidly became evident that it would have to be utterly different from anything that was built. The big issues were weight and loading gauge.
Firstly, there's no more room for outside cylinders than there is on the narrow gauge, so the sort of huge cylinders seen on US types and even metre gauge types are impractical. It leads one towards a 4 cylinder compound, because small outside cylinders are mandated, hence high pressure ones, but there's plenty of room for truly enormous low pressure cylinders between the frames, so the division between high and low pressure can be much better managed than  is normally the case.
And now the boiler. Yippee, I thought, plenty of room for a really big efficient boiler and a wide grate between the frames. We can have the best aspects of wide and narrow fireboxes.  And so we can, except I'm not sure what that would look like. But hang on: the eaves are rather low on the broad gauge. My huge boiler probably can't have a belpaire firebox unless we back it down a bit in size. Unless it has a round top box the firebox corners are a big limitation. But a bigger issue is weight. Lets say I have a 22 ton axle weight limit. My boiler just can't be much bigger in diameter than a King or Duchess boiler, because what's going to carry the weight? Driving wheels are close to touching on those anyway, can't fit another pair in under the shorter fatter boiler. 
And so it goes on. I decided that I couldn't sketch up something reasonably credible without a far greater understanding of steam locomotive design than I possess. Starting from standard gauge deigns just didn't work for me.

So to take full advantage of 7ft gauge, you really need a taller vehicle envelope, and track & structures suitable for say 30t axle loads.

Edited November 23, 2022 by rodent279

[AlfaZagato]

Could envision something like a Yorkshire boiler, or two parallel boilers.   Maintenance on two boilers would be a pain, but two 3.5' boilers I'd wager could make plenty of steam for huge cylinders.

The high-pressure water-tube boilers might have worked in a Brunelian gauge, too.

[rodent279]

It's possible that the ability of a broad gauge loco, built to substantially the same loading gauge as standard gauge, to pull, might not be much greater than the standard gauge designs that evolved. Where it might win out is that each wagon or passenger car might not need to be as long to carry the same payload.

Edit:- so potentially fewer axles for the same payload, less rolling resistance, less weight.

Edited November 23, 2022 by rodent279

[JimC]

13 minutes ago, rodent279 said:

So to take full advantage of 7ft gauge, you really need a taller vehicle envelope, and track & structures suitable for say 30t axle loads.

And most of all a good six inches extra platform clearance.  Here's a sketch of the GWR broad gauge loading gauge against a current NR standard. It gets you gloriously wide coaches, and high containers fit (single stacked only though) and the exhaust in the centre  is well clear of the passengers, but the eaves are so low that double deck stock would be impractical.
Its a largely irrelevant consideration now, but in the early days a lot of lives were probably saved because coaches with bodies between the wheels overtuned a lot less often in the all too frequent derailments of the era.

Edited November 23, 2022 by JimC

[tythatguy1312]

11 minutes ago, AlfaZagato said:

Could envision something like a Yorkshire boiler, or two parallel boilers.   Maintenance on two boilers would be a pain, but two 3.5' boilers I'd wager could make plenty of steam for huge cylinders.

The high-pressure water-tube boilers might have worked in a Brunelian gauge, too.

I've heard anecdotes from the Ffestiniog that 2 boilers are a pain. Wouldn't be surprised if crews from Ballybunion thought the same. This COULD be solved by either oil firing or mechanical stokers though

Edited November 23, 2022 by tythatguy1312

[DenysW]

2 hours ago, JimC said:

I've tried thinking about what a big say 1930s British 7ft gauge locomotive would look like, and its a surprisingly difficult challenge.

 A British one would almost certainly have been a non-starter in the impressiveness stakes. One reason that Brunel's gauge couldn't be implemented in the 1840s trials in a way to destroy Stephenson's gauge in terms of power, speed, etc. etc. (Brunel's claims) was that both competing systems were designed at 18 tons/axle on the rails/civil structures, and on curves (mostly at points, MPDs, sidings etc.) that gave very similar maximum rigid wheelbases. Thus the same maximum 3-4 driving axles, giving 14-18 tons maximum tractive effort. So 7' gauge only had a bit of a thermal efficiency advantage over Standard Gauge, coming from better boiler aspect ratio. Purists will also note that the technology of the 1840s did not seem up to linking express driving wheels together, meaning express singles competed with each other on the two gauges, and 0-6-0s competed for goods supremacy at lower speeds. Express 2-4-0s came 10-20 years later.

 

But even by the 1930s in Britain you were pushing your luck to go much more than 21 tons/axle - on both gauge's heritage civil structures. And GWR had decided that 65' was the maximum that you should assume was available at turning circles. LMS/LNER went up to 70', and Union Pacific's Big Boys needed 130'.

 

Now had the Erie's 6' gauge survived the US economic forces from 1860-1880 you might have had a battle for which gauge was best. I note that GWR was still financially held back by the costs of first dual gauge then getting rid of the 7' gauge and the baulk track well beyond the 1890s, and the Erie went bankrupt twice in this period, partly driven by the costs of going first to dual gauge, then to Standard gauge.

 

I also note the Virginian Railway's 12' loading gauge (and their AE class locomotives) with amazement, but it wasn't a railway designed to have interconnections with other company's rolling stock. I do wonder if it was actually a 12"=1ft model railway, as it was paid for out of personal wealth.

[The Johnster]

Brunel was constrained by the same issues of axle loads and the size that the biggest locomotives could be made in the early days as the standard gauge people, and his broad gauge was not significantly different in terms of loading gauge.  His principle purpose was to improve the ride of his coaches and wagons in the belief that higher speeds could be safely achieved, and to use shorter, wider, vehicles (and hence shorter trains than standard gauge for the same load hauled, with shorter loops, sidings, and platforms).  
 

So putative British 7’ gauge 1930s locomotives may well not have been radically different to standard gauge ones.  Fireboxes could have been wider and shorter, but an 8P Pacific or 4-6-0 or 8F 2-8-0 is as big as was ever needed in the UK, and the later 9F came into it’s own on a railway that was beginning to feature fast block goods trains. 
 

Gauge, within limits, is not that important, so long as it is constant across a network, and a network may involve more than one country or even more than one continent; anything between 3’6” and double that will do the job pretty well.  Loading gauge is a much more important factor.  
 

There is a value on narrower gauges for hilly country where curvature needs to be tight, and because the wagons are smaller and cannot handle large heavy loads, you can get away with lighter rail as well. Going to the other extreme, larger than broad gauge, one quickly gets into Breitsprurbahn/Snowpiercer territory, and practicality in the form of longer approach ramps for overbridges and the cost/difficulty of building the large-bore tunnels, as well as the very solid trackbed foundations needed, make this sort of thing left to insane dictators with plenty of slave labour on tap, or entertainment/fiction/storytelling, and other situations where rational application of the laws of physics is not a consideration. Railways are usually built to make a profit, so schemes like these where the costs make the whole scheme unlikely to ever be viable are therefore unlikely to ever be built; even Hitler, who usually got his own way, never actually managed this trick!

[rockershovel]

Looking at the vast goods and ore trains running on the US and Australian systems (the phosphate trains on the Tunisian metre gauge are quite impressive, too) , the huge US axle loadings and loading gauge and the 17' maximum height on the Russian 5' gauge it's apparent that the 7' gauge was simply an aberration arising from the technical limits of the era. 

 

Another thing nobody ever mentions - how about the high-density urban services of the Southern Railway? 

[DenysW]

Is it me , or is @JimC's loading gauge sketch confusing? Yes to the 7' gauge outline. Yes to the yellow outline, which is what you get when you run 3-rail mixed gauge on one trackbed. But the grey outline seems to be the purely theoretical outline for 4-rail mixed gauge. The only photos I've seen of GWR mixed gauge (and the short section of narrow/standard gauge in Welshpool) are of the 3-rail type.

 

Brunel's choice of a loading gauge the same 27" wider than the rails as Stephenson's loading gauge allowed mixed gauge to work properly: the wagons and carriages for the narrower gauge still fitted the platforms. Had Brunel followed Stephenson's logic (loading gauge width = twice rail gauge) then there would have been a big gap and much more bickering.

[JimC]

5 hours ago, DenysW said:

Is it me , or is @JimC's loading gauge sketch confusing?

I hope not too confusing:-) Its part of a whole series of loading gauge drawings superimposed on the BR gauge, and all the rest are centred so both rails coincide. To my mind the centre alignment is good for seeing how different in size the loading gauge is. Its certainly not a representation of anything one might have seen on the road. Mind you I sometimes idly wonder how rail wear worked out on the mixed gauge, with one rail seeing so much more use than the other two. If you are interested the rest of the drawings are in the page linked in my sig.

 

 

Edited November 24, 2022 by JimC

[PhilJ W]

7 hours ago, DenysW said:

Brunel's choice of a loading gauge the same 27" wider than the rails as Stephenson's loading gauge allowed mixed gauge to work properly: the wagons and carriages for the narrower gauge still fitted the platforms. Had Brunel followed Stephenson's logic (loading gauge width = twice rail gauge) then there would have been a big gap and much more bickering.

The solution in that case would be gauntleting, as used in the USA where passenger and freight share the same tracks but the freight cars are wider than the passenger cars and would foul the passenger platforms.

[tythatguy1312]

11 hours ago, DenysW said:

Brunel's choice of a loading gauge the same 27" wider than the rails as Stephenson's loading gauge allowed mixed gauge to work properly: the wagons and carriages for the narrower gauge still fitted the platforms. Had Brunel followed Stephenson's logic (loading gauge width = twice rail gauge) then there would have been a big gap and much more bickering.

I frankly doubt the bridge at Saltash would've ever been constructed under this system, but it might've been truly gargantuan and left Britain with 2 separate rail gauges permanently

[Jeremy Cumberland]

I think the answer is that gauge (broad v standard) makes relatively little difference compared with the difference from when railways were first developed in a country and the degree of urbanisation. Take a look at this map of the railways of Europe in 1850, from this site: https://commons.princeton.edu/mg/european-railroads-in-1850/. Britain seems chock full of railways, but most of Europe is still a blank canvas:

https://commons.princeton.edu/mg/wp-content/uploads/2017/04/MG-European_Railroads_in_1850.jpg

Source: Donald Kagan et al. The Western Heritage Since 1300. (p. 746). Prentice Hall [Pearson]

Copyright © 2004 Prentice Hall [Pearson] [Sorry, I cannot get the map to display]

 

Consider, too, the populations., Four of the worlds biggest citiies in 1850 were in Britain (London, Liverpool, Manchester and Glasgow, in that order). London (population 2.3 million) was nearly twice the size of the largest city in mainland Europe (Paris, 1.3 million). The two next biggest cities in Europe were Istanbul and St Petersberg, and the one after that was Berlin with a population of about 450,000, only slightly larger than Liverpool or Manchester.

 

And what did locomotives look like in 1850? Inside cylinders, mostly. There wasn't really the pressure for width, nor really for height. I imagine that by 1850, railway builders could foresee trains getting bigger in the near future, and planned their lines accordingly, but when most of the trunk lines in Britain had already been built, there wasn't really much point in an engineer deciding to make their own line bigger; they were rarely starting from scratch in any case.

Edited November 24, 2022 by Jeremy C

[john new]

2 hours ago, Jeremy C said:

I think the answer is that gauge (broad v standard) makes relatively little difference compared with the difference from when railways were first developed in a country and the degree of urbanisation. Take a look at this map of the railways of Europe in 1850, from this site: https://commons.princeton.edu/mg/european-railroads-in-1850/. Britain seems chock full of railways, but most of Europe is still a blank canvas:

https://commons.princeton.edu/mg/wp-content/uploads/2017/04/MG-European_Railroads_in_1850.jpg

Source: Donald Kagan et al. The Western Heritage Since 1300. (p. 746). Prentice Hall [Pearson]

Copyright © 2004 Prentice Hall [Pearson] [Sorry, I cannot get the map to display]

 

Consider, too, the populations., Four of the worlds biggest citiies in 1850 were in Britain (London, Liverpool, Manchester and Glasgow, in that order). London (population 2.3 million) was nearly twice the size of the largest city in mainland Europe (Paris, 1.3 million). The two next biggest cities in Europe were Istanbul and St Petersberg, and the one after that was Berlin with a population of about 450,000, only slightly larger than Liverpool or Manchester.

 

And what did locomotives look like in 1850? Inside cylinders, mostly. There wasn't really the pressure for width, nor really for height. I imagine that by 1850, railway builders could foresee trains getting bigger in the near future, and planned their lines accordingly, but when most of the trunk lines in Britain had already been built, there wasn't really much point in an engineer deciding to make their own line bigger; they were rarely starting from scratch in any case.

Concur. I think it is also significant that in mainland Europe threat of invasion/intention to invade was far more significant a factor relating to land transport in C18 & C19 Europe than here in Great Britain. The power players all had land borders, here in GB we had a wet frontier and therefore naval supremacy was for more important. Even in peacetime sea borne trade was highly significant.

 

A new avenue of early railway research for me was recently opened up after listening to a Zoom lecture by the historian Anthony Dawson - the topic of how the UK, and in particular the army's attitude to horses compared with the French and that also then knocked on to why the steam locomotive evolved post 1800. The win at Trafalgar changed the proposals for transport development of the South East of England in a very big way. In my ERC conference paper on the development of the route to Portsmouth that regaining of naval supremacy is a significant factor.* The outcome being that several draft plateway and seriously grand canal schemes were dropped.

 

* New, J. R., 2019. Linking the Thames and Spithead: The evolution of the Portsmouth Main Line.. In: Chrimes, B., ed. EARLY MAIN LINE RAILWAYS 2. UK: Early Railways Conference Committee, 111-128.

 

 

Edited November 24, 2022 by john new
Typo correction/formatting in the book reference.

[DenysW]

5 minutes ago, john new said:

in mainland Europe threat of invasion/intention to invade was far more significant a factor relating to land transport

I think I agree, but I then find it odd that only the Russians were paranoid enough to have a different gauge from their neighbours.