The benefits/drawbacks of narrow/broad guage, could any of these systems find use in the UK?

[Jozhua]

How useful of a costcutting measure is narrow guage rail construction and would it be of any use in the UK?

To a certain extent, I can see how the UK's system could be classed as being restricted in guage regardless, due to the small loading guages our older infrastructure imposes upon us!

Whilst the idea probably seems a bit crazy and obviously interoperability is a consideration, most of Japan's railways run with a 1067mm guage up to 75mph. They seem to have quite a large network and I wonder wether the cost savings have helped it become so widespread and efficient?

Obviously the high speed trunk routes are 1435mm, which is good for stability and capacity where needed.

On the other end of the spectrum, what benefits can broader guage rail bring, like the Iberian guage? What kind of loading guage do you need before sizing up from 1435mm becomes a requirement?

Another thought on interoperability is guage changing technologies. Some Spanish trains can now have their guages adapted at roll-through facilities without the requirement to even stop! Obviously they have to be built with specialised bogies, but it's still impressive.

Sorry if this is rambly or a bit wierd (I did post it in speculative ideas for a reason!) Just want to have fun with some hypotheticals and talk about the pros and cons of the different systems

 

[AM9]

How useful of a costcutting measure is narrow guage rail construction and would it be of any use in the UK?

To a certain extent, I can see how the UK's system could be classed as being restricted in guage regardless, due to the small loading guages our older infrastructure imposes upon us!

Whilst the idea probably seems a bit crazy and obviously interoperability is a consideration, most of Japan's railways run with a 1067mm guage up to 75mph. They seem to have quite a large network and I wonder wether the cost savings have helped it become so widespread and efficient? ...

Whilst most of the Japanese network is 1067mm gauge, on most of that the loading gauge is slightly larger than the UK one which of course runs on 1435mm gauge track. That is also true for the South African main lines. On a conventional railway, I doubt that there will ever need to be anything greater than 1435 which has proven it's capability both at high speed and load capacity, (e.g. the Betuweroute and heavy, large loading gauge railways like the US and Canadian transcontinental lines. I doubt that the Russian/Soviet gauge of 1520/1524mm or the Indian 1676mm broad gauges materially affect the capacity of those lines as much as modern 1435mm developments and larger loading gauges have done.

 

[PeterC]

My inner train spotter would love it of course.

On a more serious note I think that, without the need to drop coal trucks off at every hamlet, interoperability isn't quite the issue that it was. I wouldn't seriously suggest reguaging existing lines but given the space constraints in some cities would there be an advantage in going for a narrower guage for trams? Metre guage is common in Europe after all.

 

[Jozhua]

My inner train spotter would love it of course.

On a more serious note I think that, without the need to drop coal trucks off at every hamlet, interoperability isn't quite the issue that it was. I wouldn't seriously suggest reguaging existing lines but given the space constraints in some cities would there be an advantage in going for a narrower guage for trams? Metre guage is common in Europe after all.

I've been doing some poking around on Wikipedia and found some interesting stuff, especially in Spain! The Palma Metro, opened in 2007 runs on metre gauge railway. From what I can tell, one of the two lines is based off an existing route, but the other is new.

Barcelona Metro Line 8 uses metre, although this was originally opened in 1912. The Bilbao metro (opened in 95) also uses metre gauge, although some of the outer parts of lines were absorbed from the national metre gauge network.

 

[AM9]

I've been doing some poking around on Wikipedia and found some interesting stuff, especially in Spain! The Palma Metro, opened in 2007 runs on metre gauge railway. From what I can tell, one of the two lines is based off an existing route, but the other is new.

Barcelona Metro Line 8 uses metre, although this was originally opened in 1912. The Bilbao metro (opened in 95) also uses metre gauge, although some of the outer parts of lines were absorbed from the national metre gauge network.

The only real benefit of narrow gauge is the ability to employ tighter curves, which is one of the reasons why tramways often (mostly) use narrower gauges. That advantage also becomes useful on mountain railways, but on mainline (mostly including metros) the exisiting corridors are the limiting factor in terms of capacity by virtue of their constraints on the loading gauge, (see my earlier post on the Japanese 3ft 6in lines), - they manage to run trains slightly larger than UK stock, so if excessive tight turns weren't an issue, those lines could run as standard gauge routes, as have some of the 'mini-shinkahnsen' conversions.

 

[Belperpete]

I think there is some benefit for metro and tram lines in having a smaller track gauge, as it allows sharper curves, which can be important in street situations and fitting in an already congested urban environment. You can get substantial bodies on small gauges - look at the SAR garrats. The drawback being the larger the body and the smaller the gauge, the lower the maximum speed - likely not a major issue with metros and trams. I understand that double Fairlies were known to do some quite impressive speeds on the Ffestiniog in the days when it was a proper working railway.

For a broad gauge to be worth it, it would need to be substantially wider, say like the old GW 7ft gauge, with a substantially bigger structure gauge to match. So you could get 4 containers on a wagon, 2 wide and 2 high. But then axle loading would start to be a problem. And the costs of bridges and tunnels would increase substantially. Combined with all the interoperability problems, particularly for freight, I don't really see much of a case for broad gauge.

 

[Bletchleyite]

My inner train spotter would love it of course.

On a more serious note I think that, without the need to drop coal trucks off at every hamlet, interoperability isn't quite the issue that it was. I wouldn't seriously suggest reguaging existing lines but given the space constraints in some cities would there be an advantage in going for a narrower guage for trams? Metre guage is common in Europe after all.

You can build to a smaller loading gauge rather than track gauge, though? Some trams are even narrower than buses but still run on 4' 8.5".

 

[Jozhua]

You can build to a smaller loading gauge rather than track gauge, though? Some trams are even narrower than buses but still run on 4' 8.5".

I guess it's to do with those turning radius'

Just wondering, does a narrow guage turn of quite a tight radius have higher turning speeds than standard guage? Systems like Metrolink employ quite tight curves and the trams crawl & grind their way through them...

 

[AM9]

I guess it's to do with those turning radius'

Just wondering, does a narrow guage turn of quite a tight radius have higher turning speeds than standard guage? Systems like Metrolink employ quite tight curves and the trams crawl & grind their way through them...

On a very tight radius curve, the difference between the distance travelled by the inner wheel tread is much less than that on the outer one, so one or both of them scrub the track creating the wheel howl. Also the centering effect of the wheel profile ceases to work in the same way and flange contact will also create seal, (which means wear). At higher speeds, there is probably a risk of the outer wheel flanges riding up and causing a derailment.

 

[Bletchleyite]

On a very tight radius curve, the difference between the distance travelled by the inner wheel tread is much less than that on the outer one, so one or both of them scrub the track creating the wheel howl. Also the centering effect of the wheel profile ceases to work in the same way and flange contact will also create seal, (which means wear). At higher speeds, there is probably a risk of the outer wheel flanges riding up and causing a derailment.

Though you don't have to use solid axles, you can have independent wheels, and indeed I think many modern very-low-floor trams do because the axle would require a raised floor.

As an aside, the Talgo concept also delivers low floor throughout by using independent wheels rather than solid axles.

Road vehicles of course use a differential to cope with this as tyres can't slip in the same way.

 

[edwin_m]

Although narrow gauge theoretically allows tighter turns, the reduced stability may mean lower speed than a standard gauge curve of the same radius.

In the UK we have an 18m radius curve on the Nottingham tramway, and Berlin has one of 14m I believe, all on standard gauge. If light rail technology is used, there is very little that narrow gauge can do and standard gauge can't.

 

[Mojo]

I've been doing some poking around on Wikipedia and found some interesting stuff, especially in Spain! The Palma Metro, opened in 2007 runs on metre gauge railway. From what I can tell, one of the two lines is based off an existing route, but the other is new.

Barcelona Metro Line 8 uses metre, although this was originally opened in 1912. The Bilbao metro (opened in 95) also uses metre gauge, although some of the outer parts of lines were absorbed from the national metre gauge network.

And at the other end of the scale you have the Bart metro system in San Fransisco that uses Indian broad gauge; the system opening in 1972, nearly 100 years since the last heavy rail system in the US stopped using Indian gauge!

 

[AM9]

And at the other end of the scale you have the Bart metro system in San Fransisco that uses Indian broad gauge; the system opening in 1972, nearly 100 years since the last heavy rail system in the US stopped using Indian gauge!

To no real benefit I imagine.

 

[edwin_m]

And at the other end of the scale you have the Bart metro system in San Fransisco that uses Indian broad gauge; the system opening in 1972, nearly 100 years since the last heavy rail system in the US stopped using Indian gauge!

To no real benefit I imagine.

I suspect the aerospace-background BART engineers went back to first principles of what a railway should look like and decided a slightly broader gauge was optimum. In doing so they made sure they would have to buy non-standard trains and maintenance equipment until the end of time. And as they appear to have made the fundamental mistake of not providing any wheel conicity, I don't think their other decisions have much credibility.

 

[Belperpete]

Just wondering, does a narrow guage turn of quite a tight radius have higher turning speeds than standard guage? Systems like Metrolink employ quite tight curves and the trams crawl & grind their way through them...

Some of the curves on the Ffestiniog used to have quite substantial superelevation of the outer rail, so that the gravity slate trains could maintain speed.

 

[Belperpete]

I suspect the aerospace-background BART engineers went back to first principles of what a railway should look like and decided a slightly broader gauge was optimum. In doing so they made sure they would have to buy non-standard trains and maintenance equipment until the end of time.

That of course is one of the main disadvantages of a non-standard gauge. Probably not too important when a line is first built, but a real pain when you need to buy replacements.

 

[Bletchleyite]

5' 6" isn't that non-standard, it's close enough to Iberian and Irish gauge, isn't it?

 

[AM9]

5' 6" isn't that non-standard, it's close enough to Iberian and Irish gauge, isn't it?

But not interchangeable so it might as well be wildly different. As Sir Humphery would say, "a brave decision".

 

[Mojo]

The gauge is only one of many irregularities the system has. It's 1676mm, so 8mm difference with Iberian gauge. Irish gauge is 1600mm.

Bart also uses flat-edge rail, which has proven to be highly problematic.

 

[Gag Halfrunt]

But not interchangeable so it might as well be wildly different.

That's not entirely true.

The Indian gauge (1,676 mm or 5 ft 6 in) is closely similar, with only 8 mm (5⁄16 in) difference, and allows compatibility with the rolling stock. For example, in recent years Chile and Argentina have bought second hand Spanish/Portuguese Iberian-gauge rolling stock. 1,668 mm trains can run on 1,676 mm gauge without adaptation, but for better stability in high-speed running a replacement wheelset may be required...

 

[Jozhua]

And at the other end of the scale you have the Bart metro system in San Fransisco that uses Indian broad gauge; the system opening in 1972, nearly 100 years since the last heavy rail system in the US stopped using Indian gauge!

Oh yeah, I believe some other US metros use non standard guages too!

One SEPTA line is 1581mm, built to Pennsylvenia Trolley guage. Pittsburgh light rail also makes use of this.

The Washington Metro was built to 1429mm!

 

[MarkyT]

Indian and Iberian gauges are very nearly the same, which explains parts of S. America, with the Iberian only 8mm short of 5ft 6in, so a standard Spanish track machine probably wouldn't fall off the rails on BART. The really weird one is Irish, 3 inches short of Indian/Iberian and also used in Australia. It's not irrational to have wanted an appreciably wider gauge for heavy haul networks in the colonies that would likely never be connected to Europe or N. America, but it beats me why the British Empire didn't standardise on one broader option for commonality of supplies. Russia is another matter altogether. There's a good case to be made that 5ft was a deliberate strategic measure so a full gauge conversion would have to be made by any invading power, slowing down the advance. What I mean by that is Russian is too close to standard gauge to allow a three rail solution to work, as the webs of the rails interfere and there's not enough room for a flange between them even if you made special rails for the purpose. If an invader wishes to bring his own SG trains onto the Russian network. He must first regauge entirely rather than 'simply' adding a third rail as he goes, which then of course also makes any Russian stock left behind useless to the invader. Some tracks in the Baltic States were converted back and forth a number of times during WW2 for instance, which must have left wooden sleepers in a mangled state. I think the German BR52 'Kriegslok' was designed to be gauge convertible at overhaul, with wheels sets exchanged clearly. There were very many built new to Russian gauge for the invasion.

 

[Gag Halfrunt]

IIRC the use of Indian gauge in South America resulted from the involvement of British engineers and investors. Independent South American countries had no reason to worry about compatibility with Spain.

 

[MarkyT]

IIRC the use of Indian gauge in South America resulted from the involvement of British engineers and investors. Independent South American countries had no reason to worry about compatibility with Spain.

Quite likely, but they would likely have met no resistance from any authorities with links to the 'old countries' due to the similarity. The Spanish gauge was originally almost exactly 5ft 6in at 1674mm but was later standardised at 1668mm for better compatibility with Portugal (don't know why Portugal was slightly different to start with, but it's all within the engineering tolerance zone so they're all basically 5ft 6in in old money). A bit like the difference between Finnish gauge, which is still formally 1524mm (closest whole metric value to 5ft) and Russian, which was 'rounded down' by the Soviets to 1520mm. Again, it's no practical barrier to inter-running.

 

[hexagon789]

Whilst the idea probably seems a bit crazy and obviously interoperability is a consideration, most of Japan's railways run with a 1067mm guage up to 75mph. They seem to have quite a large network and I wonder wether the cost savings have helped it become so widespread and efficient?

No because one of the reasons for building the Shinkansen was to allow greater capacity but also speed. Only 6 years before The Tokaido Shinkansen opened the maximum speed on Japanese railways was 95km/h. Electrification pushed that to 110 in 1958 but the tightness of curves even today precludes higher than typically 120-130 without tilting or long straight sections.

On the other end of the spectrum, what benefits can broader guage rail bring, like the Iberian guage? What kind of loading guage do you need before sizing up from 1435mm becomes a requirement?

I think that depends on whether it was widespread. You have of course the famous example of Brunel's broad against Stephenson's "standard", the former being ruled against because there was more 4ft 8.5in and interoperability was considered desireable. Had the situation been reversed I could see the broad guage having been taken to.

 

[adamedwards]

Looking forward to the Caernarfon to Aberysthwyth Welsh Highland Talgo with guage changer at Porthmadog. Over to speculators to suggest where a second portion could also run from...

 

[edwin_m]

The reason for the Irish gauge is apparently that three different railways were started on three different gauges. The government recognized the evident ridiculousness of this and appointed an eminent person to adjudicate. His answer was to take the average of the three, which wasn't the same as any of the existing ones or as any gauge yet proposed worldwide. Then of course South Australia employed an Irish engineer and the rest is history...

 

[HSTEd]

The only reason to go to a non standard gauge is if we are going to go for something huge like the Breitspurbahn gauge.

Otherwise there is little reason to change.
The loading gauge on the other hand is another matter entirely.

 

[Jozhua]

The only reason to go to a non standard gauge is if we are going to go for something huge like the Breitspurbahn gauge.

Otherwise there is little reason to change.
The loading gauge on the other hand is another matter entirely.

Just looked that up and it looks pretty epic...

Swimming pools on trains!

Damn, wish it got built after the war, perhaps by a less terrible regime...

 

[PeterC]

Oh yeah, I believe some other US metros use non standard guages too!

One SEPTA line is 1581mm, built to Pennsylvenia Trolley guage. Pittsburgh light rail also makes use of this.

The Washington Metro was built to 1429mm!

I have a recollection of reading that the trolleys in the USA were required to be non standard in guage to prevent them competing with the regular railroads.