Talk:Track gauge

This paragraph contains a lot of conjecture

Track gauge#Advantages and disadvantages of different track gauges
For example, the BART choose 5 ft 6 in (1,676 mm) because the wider gauge would give greater stability in case of high cross winds. eBART uses standard gauge. Peter Horn User talk 18:25, 18 May 2017 (UTC)

I'm currently researching this again, and editing out info with less support. Bigdan201 (talk) 10:55, 29 May 2017 (UTC)

The possible top speed on standard gauge and broad gauge , as determined by the laws of phisics, is the same. at a certain high speed the train tends to literally fly of the rails. This requires a bit of digging. Peter Horn User talk 01:55, 8 June 2017 (UTC)

Digging is right. According to old engineering journals I've read, track gauge does not have a significant relationship with curvature; that it does is a common misconception. Apparently, wider gauge may impose a very slight restriction on turning radius, but for practical purposes it is not meaningful. I certainly never meant to post misinformation, so pardon me for that. It's a tricky topic with scattered information, I'm trying my best to collate it together. Bigdan201 (talk) 10:43, 8 June 2017 (UTC)

Bigdan201 and Peter Horn Agreed, the information about advantages and disadvantages between narrower gauge and broader gauge railways is not at all clear. And as Bigdan201 said, the information on the net is scattered too. Most of the websites out there seem to provide wrong info regarding comparison. So, as of now, I have tried to remove conflicting statements and tried to make the section more clearer. Still the section requires good references. Or else for better, the section could be removed altogether.

Vatsmaxed (talk) 17:01, 1 May 2020 (UTC)

May I help to clarify a bit? I have experience in planning of high-speed rail lines (though not as a civil engineer).

In the 19th and early 20th centuries, when most narrow gauge lines were built, commerce was not very time-sensitive. In an age when the alternative mode was animal-hauled, the fact that you could get your freight to its destination with a degree of reliability was the huge competitive advantage. With investment limited to what the market would come up with, building a line as cheaply and quickly as possible was crucial to giving a good return on investment. With resources limited to horse-drawn implements, humans with hand tools and the occasional explosives, the over-riding task was to minimise earthworks. Given that locomotives of the time were limited in power and that steep gradients were anathema to slow-speed trains, that meant going around contour lines. This gave two advantages for narrow gauge: first, as mentioned, smaller dimensions, hence lighter weight, of rolling stock required smaller earthworks (the saving through the gauge being, say, 1 foot to 1'-6" narrower was relatively minor in this); second, because their wheelbases were shorter, narrow-gauge steam locomotives were able to negotiate the tighter curves mandated by the need to "crawl around the contours" — and in fact even then, narrow gauge loco wheelbases were a limiting factor until articulated locos were developed (see Garratt article).

So, respectfully, I would argue that "wider gauge may impose a very slight restriction on turning radius, but for practical purposes it is not meaningful" is incorrect.

For a striking example of this factor, in Google Maps, select satellite view and key in "Yanga, Gladstone South Australia" then click, once or twice, to a higher view. The winding alignment is the 1880 narrow gauge, the almost straight railway adjacent is a 1970 replacement in standard gauge. And the terrain isn't all that hilly, as you'll see if you go to Street View. The size of the earthworks needed to attain that almost straight route can be seen if you "drive" north-east for a few hundred yards and look to the right, where you'll see a long embankment. Constructing that single embankment required vastly more earth to be moved than in the entire section of the narrow gauge, I'll bet.

How would I encapsulate this? Maybe something like this, which I'll only propose for further discussion and decisions on your part, because it's "top of the head" — I no longer have references to hand on account of being overseas from my home:

The gauges of railways often have their origins in decisions made in the era of railway development – the second half of the 19th century and early years of the 20th. The choice for any given railway was usually founded not only on the terrain but also on the economic and political history of the area in which it was built. Often, a narrow gauge was chosen to keep within a very small budget when a line was initiated to develop economically promising resources, whether agricultural or mineralogical. Narrower gauge railways cost less to build, for several reasons. First, the dimensions of locomotives and rolling stock were smaller in order to limit train weight on track and bridges and to limit the amount of rock to be removed in tunnels. Second, to maximise the tonnage that could be hauled by low-powered steam locomotives of the time, track had to be built as level as possible. That necessitated trains going around contour lines if earthworks were to be kept to a minimum, which was necessary when horse-drawn implements, humans with hand tools, and occasional explosives were the only available resources. Third, because narrow-gauge steam locomotives were smaller than those of the larger gauges, their wheelbase – the distance between the centres of the front and rear wheels – was shorter, allowing them to negotiate tighter curves. Eventually, development of articulated designs such as the Garratt allowed powerful locomotives to operate on such track.

The place of political history in the choice of gauge was, in newly developing countries or colonies, related to the gauges already established in the territories of the particular colonial power.

Narrow gauge is thus often used in mountainous terrain, where the savings in civil engineering work can be substantial. It is also used in sparsely populated areas, with low potential demand, and for temporary lines that will be removed after short-term use, such as for construction, the logging industry, the mining industry, or large-scale construction projects.

Broader gauges (especially standard gauge) are generally more expensive to build because characterisitcally larger rolling stock and locomotives mandate a larger loading gauge and heavier engineering. The trade-off is usually their higher speed and tonnage capacity. However, some modern narrow-gauge lines approximate the capacities of broader gauge equivalents.

Cheers, Simon. SCHolar44 (talk) 12:26, 2 May 2020 (UTC)

@Bigdan201:, @Vatsmaxed: Would physicists be able to calculate at what speed a train would fly of the track or would that take running an automated train on an adequate length of test track? The latter would be a spectacular way to wreck / scrap a train! Trains on 1,067 mm (3 ft 6 in), 1,000 mm (3 ft 3+3⁄8 in) metre gauge or 914 mm (3 ft) would probably never reach that speed. Minimum railway curve radius can affect the pivot distance between the bogies and thus the overall length of the rail vehicle Peter Horn User talk 18:22, 1 May 2020 (UTC)

Peter Horn Agreed. Vatsmaxed (talk) 07:47, 2 May 2020 (UTC)

It's not difficult to calculate. In fact my late colleague, Paul Wild, who led Australia's first but unsuccessful (like all the others) high-speed rail project, used to write exam qustions for physics students in their final year before going to university, and I remmebr one to that effect. In practice, passenger comfort (or rather the lack of it) takes place well before there is any such prospect. That's why a minimum horizontal radius of 7 km / 4 mi was specified for 350 km/h trains.

As for your practical suggestion, Peter, a trainee physicist, otherwise known as a locomotive driver, put it in place in February by approaching a 15 km/h turnout at about 80 km/h: see here .  :-) Cheers, Simon. SCHolar44 (talk) 12:26, 2 May 2020 (UTC)

Conflicting Information in Paragraph "Gauge selection in other countries"

Previously today I read in a Wikipedia article that the ideas that governments selected track gauge with military defense in mind and that narrower gauges allow for tighter turning radiuses are misconceptions. This paragraph states both. What is the real story?Fearga (talk) 21:59, 28 August 2017 (UTC)John Shanahan

Fearga, Real story seems to be mostly "individual choice". Also see my reply above. Vatsmaxed (talk) 17:02, 1 May 2020 (UTC)

Minimum-gauge – better defined as "less than 2 ft or 600 mm" ?

As I interpret the section on minimum-gauge, it is defined as "smaller than 2 ft, which equals 610 mm". I would rather say "smaller than 2 ft or 600 mm". In Sweden and, I think, other European countries, there were numerous 600 mm railways built. They had a small gauge, but were not regarded "minimum". Some were by the Decauville design, with light and pre-fabricated pieces, while others were regularly built railways. Fomalhaut76 (talk) 17:10, 4 August 2020 (UTC)

I'd say: look at to definition (in sourced) of the "minimum gauge" first. Follow its units, don't extrapolate the definition (to mm's then). -DePiep (talk) 18:58, 4 August 2020 (UTC)

Finnish gauge is 1524 mm, not 1520 mm

Finnish gauge is 1524 mm page 10. It has never been 1520 mm. The change from 1524mm to 1520mm was done in the Soviet Union, and Finland has never been a part of the Soviet Union. — Preceding unsigned comment added by Zenfox (talk • contribs) 09:03, 21 December 2020 (UTC)

"1520 mm" and "1524 mm" are both considered to be "Russian gauge". Russian railroads started defined in Imperial units: 5 ft (1,524 mm), then later the definition was changed to metric being 1,520 mm (4 ft 11+27⁄32 in) (1960). The difference was only 4 millimetres (0.16 in) then, so no rail had to be relaid and rolling stock kept unchanged.

So if the "1520 mm" is not in the sources for Finland, your point is right. That is: Finland never metrificated the definition. (Rolling stock is still ordered by the imperial size). Article(s) on Finnish railroads could refine this point.

OTOH, in this article Track gauge, both sizes are grouped into one class: "5 ft and 1520 mm gauge railways". For the purpose of this article, that is fine (there are some 250 different gauges defined, see this list). So here, Track gauge § Dominant railway gauges, Finland should stay in this class.

One might want to check these articles for correctness: Rail transport in Finland, History of rail transport in Finland (has no track gauge mentioned).

I conclude: this edit is correct, I will reinstall it. This removal of Finland from "5 ft and 1520 mm gauge railways" (bolding added) seeems incorrect, as both sizes are called "Russian gauge". -DePiep (talk) 17:11, 21 December 2020 (UTC)

References

Iberian gauge on map

What about changing the map for a map displaying the Iberian gauge in the Iberian peninsula (Spain and Portugal), instead of this incorrect map that shows standard gauge? 37.170.58.217 (talk) 11:56, 15 March 2022 (UTC)

Italian metre gauge

Why not include 950mm in the list of gauges?--Oldboltonian (talk) 14:06, 6 June 2022 (UTC)

Narrow gauge

Move the sentence about the Battle of the Gauges to be clearer that the following sentence about mountain railways refers to the modern usage of narrow as less than standard, rather than to the Stephenson gauge? Tom Permutt (talk) 04:03, 24 October 2022 (UTC)

1620 mm gauge

See Openrailwap permalink 1 in Lille where one metro one line seems to be dual track (1435 mm / 1620 mm) while the other line is only 1620 mm. These are Rubber-tyred metro's where tyres run on metal bands wich are 1620 mm apart. Line two has been build without the normal gauge guiding rails. Example: File:Lille Metro Quatre Cantons - Grand Stade empty train 2.jpg

The other 1620 mm railway line is Orly Val: Openrailwap permalink 2. Should we treat this as a 1620 mm track gauge or explain the situation with Rubber-tyred metro's. Luckely there are no other gauges with Rubber-tyred metro's.Smiley.toerist (talk) 12:59, 9 April 2024 (UTC)