Track gauge
By transport mode
Tram · Rapid transit
Miniature · Scale model
By size (list)

  Fifteen inch 381 mm (15 in)

  600 mm,
Two foot
597 mm
600 mm
603 mm
610 mm
(1 ft 11 12 in)
(1 ft 11 58 in)
(1 ft 11 34 in)
(2 ft)
  750 mm,
Two foot six inch,
800 mm
750 mm
760 mm
762 mm
800 mm
(2 ft 5 12 in)
(2 ft 5 1516 in)
(2 ft 6 in)
(2 ft 7 12 in)
  Swedish three foot,
900 mm,
Three foot
891 mm
900 mm
914 mm
(2 ft11 332 in)
(2 ft 11 716)
(3 ft)
  Metre 1,000 mm (3 ft 3 38 in)
  Three foot six inch,
Cape, CAP, Kyōki
1,067 mm (3 ft 6 in)
  Four foot six inch 1,372 mm (4 ft 6 in)

  Standard 1,435 mm (4 ft 8 12 in)

Five foot
1,520 mm
1,524 mm
(4 ft 11 2732 in)
(5 ft)
  Irish 1,600 mm (5 ft 3 in)
  Iberian 1,668 mm (5 ft 5 2132 in)
  Indian 1,676 mm (5 ft 6 in)
  Six foot 1,829 mm (6 ft)
  Brunel 2,140 mm (7 ft 14 in)
Change of gauge
Break-of-gauge · Dual gauge ·
Conversion (list) · Bogie exchange · Variable gauge
By location
North America · South America · Europe · Australia

With railways, a break-of-gauge occurs where a line of one gauge meets a line of a different gauge. Trains and rolling stock cannot run through without some form of conversion between gauges, and freight and passengers must otherwise be transhipped. A break-of-gauge adds delays, cost, and inconvenience.

Advantages and disadvantages


Narrow gauges tend to be associated with smaller loading gauges and sharper curves, which tend to reduce initial capital costs. This offsets the costs of any traffic affected by the break-of-gauge. Historically narrow gauge railways were primarily built on marginal lines, mostly through hilly and mountainous terrain to cut costs and enable any type of rail service at all. Associated disadvantages were not recognized as much as many rail lines were operated independent of potentially connecting lines regardless of gauge as competing companies built and operated them. Only the building of union stations or the nationalization of railroads changed this.

An advantage is that invading armies may be severely hampered (as when Germany invaded the USSR in World War II).

Another advantage might be that if the different gauges have different loading gauges, the break-of-gauge helps prevent the larger wagons straying onto lines with smaller tunnels.[1]

Similarly, if the larger and smaller gauges use different couplers, the break of gauge tends to keep the different couplers separate.

For passengers

For passenger trains the inconvenience is less, especially at major stations where many passengers change trains or end their journeys anyway. Therefore, some passenger-only railways have been built with gauges otherwise not used in the concerned countries. For example, the high-speed railways (and some rapid transit lines) in Japan and Spain use 1,435 mm (4 ft 8 12 in) while their respective mainline railroad systems use 1,067 mm (3 ft 6 in) and 1,668 mm (5 ft 5 2132 in).

For night trains, which are very common in places like Russia, train change is less desirable. For these, often the bogies are replaced, even if it takes much more time than having passengers change trains.

For towns along the lines

If local government has influence over the construction of railways, some may see it as desirable for trains (and passengers) to stop in rather than pass through their town. For instance prior to the US Civil War, many cities in the South had a break of gauge or two separate stations at different ends of town necessitating change of trains or time consuming transshipment which nonetheless brought commerce and profit to the towns. Only during the civil war did state and Confederate authorities notice the military and economic problems this brought but only the post-bellum Union government was able to largely solve those problems through conversion of almost all lines to standard gauge.


Bogie changing in Ussuriisk (near Vladivostok) at the ChineseRussian border
One solution to the break-of-gauge problem – the transporter car

Transhipping freight from cars of one gauge to cars of another is very labour- and time-intensive, and increases the risk of damage to goods. If the capacity of the freight cars on both systems does not match, additional inefficiencies can arise. If the frequency is low, trains might need to wait a long time for its counterpart to arrive before transshipping. This is avoided by storing the goods, but that is also an inconvenience.

Technical solutions to avoid transhipping include variable gauge axles, replacing the bogies of cars, and using transporter cars that can carry a car of a different gauge.

Talgo and CAF have developed dual-gauge axles (variable gauge axles) which permit through running between broad gauge and standard gauge. In Japan the Gauge Change Train, built on Talgo patents, runs on standard and narrow 1,067 mm (3 ft 6 in) gauge.

Breaks-of-gauge are avoided by installing dual gauge track, either permanently or as part of a project to replace one gauge with another.

At most breaks-of-gauge passengers have to change trains, but there are a few trains that run through, for example, the Talgo (variable-gauge axles, see above), and trains from Russia to China or Russia to Europe (bogie exchange), although on the latter two the passengers usually have to leave the train for some time whilst the accommodation work is done.

When buying trains

Railroads of unusual gauges or loading gauges have problems procuring trains or may be forced to choose between an oligopoly or even monopoly of suppliers that cater to their specific needs. This may be deliberate on the part of suppliers as some streetcar lines were built to unique specifications to ensure buyer lock-in. However, in modern times rail gauge itself is often not the most important factor but rather other aspects like electrification system or loading gauge. Trains crossing the Channel Tunnel for instance had to be custom made prior to the construction of High Speed 1 despite both Britain and France having standard gauge, because the British loading gauge is narrower and the legacy lines in the south of Britain were electrified through third rail rather than overhead wiring.

Overcoming a break of gauge

Where trains encounter a different gauge, such as at the Spanish–French border or the Russian–Chinese one, the traditional solution has always been transshipment — transferring passengers and freight to cars on the other system. When transhipping from one gauge to another, chances are that the quantity of rolling stock on each gauge is unbalanced, leading to more idle rolling stock on one gauge than the other. This is obviously far from optimal, and a number of more efficient schemes have been devised.

Bogie exchange and variable gauge

Main articles: Bogie exchange and Variable gauge

One common method to avoid transshipment is to build cars to the smaller of the two systems' loading gauges with bogies that are easily removed and replaced, with other bogies at an interchange location on the border. This takes a few minutes per car, but is quicker than transshipment of goods.

A more modern and sophisticated method is to have multigauge bogies whose wheels can be moved inward and outward. Normally they are locked in place, but special equipment at the border unlocks the wheels and pushes them inward or outward to the new gauge, relocking the wheels when done. This can be done as the train moves slowly over special equipment.

Dual gauge and track gauge conversion

In some cases, breaks of gauge are avoided by installing dual gauge track, either permanently or as part of a changeover process to a single gauge.

Piggyback operation

Main articles: Rollbock and Transporter wagon

One method of achieving interoperability between rolling stock of different gauges is to piggyback stock of one gauge on special transporter wagons or even ordinary flat wagons fitted with rails. This enables rolling stock to reach workshops and other lines of the same gauge to which they are not otherwise connected. Piggyback operation by the trainload occurred as a temporary measure between Port Augusta and Marree during gauge conversion work in the 1950s to bypass steep gradients and washaways in the Flinders Ranges.[2][3]

Narrow gauge railways were favoured in the underground slate quarries of North Wales, as tunnels could be smaller. The Padarn Railway operated transporter wagons on their 4 ft (1,219 mm) gauge railway, each carrying four 1 ft 10 34 in (578 mm) slate trams. When the Great Western Railway acquired one of the narrow gauge lines in Blaenau Ffestiniog, they used a similar type of transporter wagon in order to use the quarries' existing slate wagons.[4]

Transporter wagons are most commonly used to transport narrow gauge stock over standard gauge lines.

At the Guinness brewery in Dublin there used to be 1 ft 10 in (559 mm) internal narrow gauge and 5 ft 3 in (1,600 mm) gauge (standard gauge for Ireland), and to avoid having to have steam locomotives of both gauges the narrow gauge engines were provided with standard gauge converter wagons (named "Haulage trucks"). The narrow gauge steam locomotive was lowered into the haulage truck using a gantry, and its wheels rested on rollers, which in turn drove the haulage wagon wheels via a 3:1 reduction gear. Several of these locomotives survived into preservation, including locomotive No23 complete with haulage wagon and lifting gantry preserved at Brockham museum in 1966, and now at the Amberley Museum Railway.

More rarely, standard gauge vehicles are carried over narrow gauge tracks using adaptor vehicles; examples include the Rollbocke transporter wagon arrangements in Germany, Austria and the Czech Republic and the milk transporter wagons of the Leek and Manifold Valley Light Railway in England.

As of 2010, Japan is developing the Train on Train piggyback concept.


Main article: Containerisation

The widespread use of containers since the 1960s has made break of gauge less of a problem, since containers are efficiently transferred from one mode to another by suitable large cranes.

It helps if the lengths of the wagons on each gauge are the same so the containers can be transferred from one train to the other with no longitudinal movement along the trains. The different wagons should carry the same number of containers. Delays to each train depends on how many cranes can operate simultaneously.

Container cranes are relatively portable, so that if the break of gauge transshipment hub changes from time to time, the cranes can be moved around as required. Fork lift trucks can also be used.

It has been reported that, for example, when containers are shipped by a "direct train" from China to Europe, it is only containers, and not the railcars, which move from China's railway network to that of Kazakhstan. At the border station at Khorgos, two trains (the Chinese standard-gauge one and the Kazakh Russian-gauge one) would stand side by side at parallel tracks, while the cranes would move the containers from one train to the other in as short time as 47 minutes.[5]

Examples of breaks of gauge



People's Republic of China

The People's Republic of China has a standard gauge network; neighbouring countries Mongolia, Russia and Kazakhstan use 1,520 mm (4 ft 11 2732 in) gauge, and Vietnam mostly uses 1,000 mm (3 ft 3 38 in) (metre gauge), so there are some breaks of gauge. See the Trans-Manchurian Railway (gauge changing at Zabaikalsk on the Russian side of the border), the Trans-Mongolian Railway and the Lanxin railway. The Yunnan–Vietnam Railway is dual gauge in Vietnam as far as Hanoi.[6] There is currently a break of gauge at Dostyk on the Kazakh border. Kazakhstan was planning to build an additional line in standard gauge[7] between Dostyk and Aktogay, but the plan was abandoned.


India currently has significant lengths of four different gauges: 5 ft 6 in (1,676 mm) Indian gauge, 1,000 mm (3 ft 3 38 in) metre gauge, 2 ft 6 in (762 mm) gauge and 2 ft (610 mm) gauge. Indian Railways has decided to convert most of its metre gauge and narrow gauge systems to broad gauge under an exercise called Project Unigauge. However, most new metro systems in India are built using standard gauge because this makes it more economical to acquire equipment from international markets.


Iran, with its standard gauge rail system, has break-of-gauge with 1,520 mm (4 ft 11 2732 in) gauge at the borders with Azerbaijan and Turkmenistan, and now also with Pakistan's 5 ft 6 in (1,676 mm) Indian gauge at Zahedan. The break-of-gauge station at Zahedan was built outside the city, as the existing station was hemmed in by built up areas.[8]


All high-speed "Shinkansen" routes in Japan have been built as standard gauge lines. A few routes, known as "Super Tokkyū", have been planned as narrow-gauge 3 ft 6 in (1,067 mm), and the conventional (non-high-speed) is mostly narrow-gauge 3 ft 6 in (1,067 mm), so there are some breaks of gauge and dual gauge is used in some places. Private railways often use other gauges.

And while most of the Japanese urban rail/metro use 1,067 mm (3 ft 6 in) rail gauge, a considerable amount of lines are still using their own different gauges including 762 mm (2 ft 6 in), 1,372 mm (4 ft 6 in), and 1,435 mm (4 ft 8 12 in).[9] This prevented the creation of some through train services.[10]

In 2010, Hokkaido Railway Company (JR Hokkaido) started working on a transporter train by trainload concept called "Train on Train" to carry narrow-gauge freight trains at faster speeds on standard-gauge flatcars. The Seikan Tunnel is being converted by JR Hokkaido to dual gauge to accommodate the Hokkaido Shinkansen.

An experimental variable gauge "Gauge Change Train" has also been tested since 1998 as a means to allow through services from high-speed standard-gauge shinkansen lines to narrow-gauge regional lines. Its first deployment is expected to be Kyushu Shinkansen Nagasaki route.

North Korea

The North Korean rail system has some breaks of gauge. Several parts of the Paektusan Ch'ŏngnyŏn Line on the stretch between Wiyŏn and Hyesan Ch'ŏngnyŏn are dual gauged to allow connections to the Paektusan Rimch'ŏl Line and the Samjiyŏn Line.[11] Also, the line connecting to the Trans-Siberian Railway from Rajin to Khasan is dual gauged for standard gauge and Russian gauge.[12]


In the 20th century, railroads on the entire Sakhalin used the same 3 ft 6 in (1,067 mm) narrow gauge as Japan, as part of it was under Japan's control when railway construction began. One stretch of rail that used 600 mm (1 ft 11 58 in) narrow gauge was converted to match the 3 ft 6 in (1,067 mm) narrow gauge after Russia took control of it.

Starting from the 1970s, a train ferry service was provided to connect Sakhalin and the Russia mainland, requiring bogie exchange on wagons to allow operation on the Russian mainland 1,520 mm (4 ft 11 2732 in) broad gauge.

In 2003, the Russian government started to convert the entire network to dual gauge with 3 ft 6 in (1,067 mm) and 1,520 mm (4 ft 11 2732 in). Work is 70% done as of 2016, and is expected to be complete by 2018. The entire island's rolling stock is expected to be replaced by 1,520 mm (4 ft 11 2732 in) rolling stock by 2020, thus eliminating the break of gauge between Sakhalin and the Russian mainland.[13]


Route of THSR shown in orange, all others are operated by TRA

Like Japan, the rail transport in Taiwan use the 3 ft 6 in (1,067 mm) gauge for the majority of its railway network, but 1,435 mm (4 ft 8 12 in) standard gauge for its high-speed rail; however, gauge differences are less of a problem as Taiwan High Speed Rail generally uses separate rolling stocks and its own discrete railway, and at most locations runs on routes kilometres away from the conventional Taiwan Railways Administration railway network.


United Kingdom

Russian gauge meeting Standard gauge

vs. Former Soviet Union countries: Russia, Lithuania, Belarus, Ukraine, Moldova (1,520 mm (4 ft 11 2732 in)). Night trains are common, and they are often bogie-exchanged.

Iberian gauge meeting Standard gauge

The earliest working example of the axle changing system at the French-Spain border in 1948 had the axles being changed at the rate of 8 waggons or 32 axles per hour.[19]

Local narrow gauge lines meeting mainlines



The break-of-gauge platform for the Sydney–Melbourne railway at Albury station; SG on left; BG on right.

The then two mainland colonies originally agreed to adopt the 4 ft 8 12 in (1,435 mm) gauge.

However, in 1850 New South Wales decided to change to the 5 ft 3 in (1,600 mm), or Irish gauge. The change was approved by the British government, and South Australia agreed to follow suit.[23] However, in 1853 New South Wales unilaterally reverted to the 4 ft 8 12 in (1,435 mm) gauge. South Australia and Victoria, the latter now separated from New South Wales, protested about the broken agreement, to no avail.


New Zealand

New Zealand originally had small lengths of lines of 3 ft 6 in (1,067 mm), 4 ft 8 12 in (1,435 mm) and 5 ft 3 in (1,600 mm), but quickly converted all to 3 ft 6 in (1,067 mm) which better suited this sparsely populated and mountainous country.

North America

South America


Minor breaks of gauge

Wherever there are narrow gauge lines that connect with a standard gauge line, there is technically a break-of-gauge. If the amount of traffic transferred between lines is small, this might be a small inconvenience only. In Austria and Switzerland there are numerous breaks-of-gauge between standard-gauge main lines and narrow-gauge railways.

Many internal Swiss railways that operate in the more mountainous regions are 1,000 mm (3 ft 3 38 in) Metre gauge and most are equipped for rack assistance to deal with the relatively steep gradients encountered.[26] Through running of standard gauge trains on rack sections would not be possible, but dual gauge track exists in many places where the gradient is relatively flat to carry standard and metre gauge stock. There also exists 800 mm (2 ft 7 12 in) gauge railways which are entirely rack operated.

The effects of a minor break-of-gauge can be minimized by placing it at the point where a cargo must be removed from cars anyway. An example of this is the East Broad Top Railroad in the United States of America, which had a coal wash and preparation plant at its break-of-gauge in Mount Union, Pennsylvania. The coal was unloaded from narrow gauge cars of the EBTR, and after processing was loaded into standard gauge cars of the Pennsylvania Railroad.

Nominal breaks of gauge

The line between Finland and Russia has a nominal break-of-gauge; Finnish gauge is 1,524 mm (5 ft) whereas Russian gauge is 1,520 mm (4 ft 11 2732 in). This does not usually prevent through-running, as the nominal 4 mm (0.16 in) difference is generally within tolerance, and the present Russian gauge is actually a redefinition of the older 1,524 mm (5 ft).

The Iberian gauge is actually three slightly different gauges. Traditionally in Spain 1,672 mm (5 ft 5 1316 in), traditionally in Portugal 1,664 mm (5 ft 5 12 in), and the newer redefined 1,668 mm (5 ft 5 2132 in). Through-running is done with vehicles having a gauge within certain tolerances. Indian gauge, 1,676 mm (5 ft 6 in), is also compatible with Iberian gauge, although there are no actual railway connections between the two, but old Spanish and Portuguese rolling stock is reused in Argentina and Chile which use Indian gauge.

A variant of Standard Gauge exists as well. The London Underground and some MTR lines use 1,432 mm (4 ft 8 38 in) rather than 1,435 mm (4 ft 8 12 in).

Other kinds of breaks

A large railway may have main lines with heavy tracks, and branch lines with light track. Light locomotives and rolling stock can operate on all lines, but heavy locomotives and rolling stock can only operate on heavy track. Heavy rolling stock might be able to operate on lighter track at reduced speed. Light track can be upgraded to heavy track by installing heavy rails, etc., and this can be done without changing the track gauge.

Gauge conversions

Gauge orphan

When a main line is converted to a different gauge, such as with Unigauge in India, branch lines can be cut off and made relatively useless, at least for freight trains, until they too are converted to the new gauge. These severed branches can be called gauge orphans.

Gauge outreach

The opposite of a gauge orphan is a line of one gauge which reaches into the territory composed mainly of another gauge. Examples include five broad gauge lines of Victoria which crossed the border into otherwise standard gauge New South Wales. Similarly, the standard gauge line from Albury to Melbourne in 1962 which eliminated most transshipment at Albury, especially the need for passengers to change trains in the middle of the night.

Two Russian broad gauge lines reach out from Ukraine, one (the Uzhhorod – Košice line) into Slovakia to carry minerals; another (the Metallurgy Line) into Poland to carry heavy iron ore and steel products without the need for transshipment as would be the case if there were a break of gauge at the border. There are plans to extend the Slovak line to Vienna.[17]

From 1994, the Rail Baltica proposal emerged to build a 728 km North–South line to link European standard gauge railways from Poland to Kaunas, Lithuania, via Riga, Latvia to Tallinn, Estonia.[27] In shorter term (decade of 2010) it will only be built to Kaunas.

The gauge outreach from Kalgoorlie to Perth partly replaced the original narrow gauge line, and partly rebuilt that line with better curves and gradients as double track dual gauge. Because of lack of space at the main Perth station, standard gauge passenger trains terminate one station short at East Perth.


Breaks of gauge are facilitated by flood lighting for night time operation, electric flood lighting not being available in the early days. Similarly heavy duty cranes only become practical once electricity supplies become available.

Other issues

While track gauge is the most important factor preventing through running between adjacent systems, other issues can also be a hindrance, including structure gauge, loading gauge, axleloads, couplings, brakes, electrification systems, signalling systems, multiple unit controls, rules and regulations, driver certification, righthand or lefthand running, repairs (how to make and pay for repairs while rolling stock is on other railway's territory) and language. The structure gauge, loading gauge and axleload problems are solved by simply using the smaller options for through running. The general solution is often to custom-build vehicles to fit all the standards to be encountered. Trains can be built to accept four voltages, to have dual signaling systems equipment, etc. All of these solutions however usually result in either more expensive trains or less comfort for passengers (e.g. through less room inside the train if it has a smaller loading gauge) or - in the case of freight railways - less room for cargo, making double stacking impossible or other negative effects.

See also


  1. "TRAMWAY LEAGUE.". South Bourke and Mornington Journal. Richmond, Vic.: National Library of Australia. February 4, 1885. p. 3 Edition: WEEKLY. Retrieved December 5, 2011.
  2. "Piggyback picture".
  4. Gray, Adrian (Winter 1994). "G. W. R. Slate Tram Transporter Wagons". British Railway Journal (50): 17–24.
  5. Shepard, Wade (2016-01-28), "Why The China-Europe 'Silk Road' Rail Network Is Growing Fast", Forbes
  6. The length of Vietnam railway network
  7. "Trans-Kazakhstan link will complete standard-gauge transcontinental artery". Railway Gazette. August 1, 2004. Retrieved April 28, 2011.
  8. Stubbs, John (January 1, 2007). "Closing the gap from Bam to Zahedan". Railway Gazette International. Retrieved May 26, 2011.
  12. "라진-하산(러시아) 철도, 10월 중순 첫 시험운행".
  14. SeaRail ferry. Retrieved 2010-03-18
  15. SeaRail Turku dual-gauge terminal
  16. "Railways in Slovakia".
  17. 1 2 "Railway Gazette: Broad gauge to Wien is feasible, says study". Retrieved 2010-12-21.
  18. Railway Gazette International Oct 2011 p48
  19. "BREAK OF GAUGE DEVICE PLEASES.". The Barrier Miner. Broken Hill, NSW: National Library of Australia. July 16, 1951. p. 5. Retrieved November 3, 2011.
  20. "THE PROPOSED RAILROAD.". The South Australian. Adelaide: National Library of Australia. December 12, 1845. p. 3. Retrieved November 28, 2011.
  21. "PROCEEDINGS OF THE LEGISALTIVE COUNCIL.". The South Australian. Adelaide: National Library of Australia. October 8, 1847. p. 3. Retrieved November 26, 2011.
  22. 1 2 "LOCAL INTELLIGENCE.". Bell's Life in Sydney and Sporting Reviewer. National Library of Australia. December 1, 1849. p. 2. Retrieved November 27, 2011.
  23. "RAILWAY PAPERS.". South Australian Register. Adelaide: National Library of Australia. August 28, 1851. p. 3. Retrieved November 27, 2011.
  24. "IT'S OFFICAL R766 to be gauge converted & head for N.S.W – Victoria – Forums – Railpage Australia". Retrieved 15 June 2012.
  25. Gary Richards, Gary Richards (April 4, 2014). "Roadshow: eBART trains along Highway 4 could be running in 2017". Contra Costa Times. MNG Corporate. Retrieved February 24, 2015.
  26. "enlarged map". Retrieved 2011-02-19.
  27. Railway Gazette International July 2011, p25.
  28. "Flinders Ranges Research Fees".
  29. "Flinders Ranges Research Email".

External links

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