Rail Gauge

Rail gauge is the distance between the inner sides of the two parallel Rails which make up a Railway track. Sixty percent of the world's railways use a gauge of 1435 Mm (4 Ft 8½ In ), which is known as the '''''standard''''' or '''''international gauge'''''. Rail gauges wider than standard gauge are called '''''broad gauge''''', and rail gauges smaller than standard are called '''''narrow gauge'''''. Some stretches of track are built to a '''''dual gauge''''': that is to say that three (or sometimes four) parallel running-rails are laid in place of the usual two, in order to allow trains of two different gauges to share the same route. The term '''''break-of-gauge''''' refers to the situation occuring at a place where different gauges meet.

HISTORY

Britain

Standard gauge was developed by the British engineer George Stephenson , designer of the Stockton And Darlington Railway , who convinced manufacturers to build equipment using the 4 ft 8½ inch (1435 mm) standard. In 1845 a royal commission recommended adoption of the standard gauge, and in the following year Parliament passed the Gauge Act, which required that new railways use standard gauge. Except for the Great Western Railway 's broad gauge, few main-line British railways used a different gauge, and the Great Western was finally converted to standard gauge in 1892 .

United States

Originally a variety of gauges was used in the United States and Canada . Some, primarily in the northeast, used standard gauge; others did not, including track gauges of up to 6 ft (1829 mm). Given the nation's recent independence from the United Kingdom , arguments based on British standards had little weight. Problems began as soon as railroads began to meet other railroads, and in much of the northeastern United States standard gauge was adopted. Most Southern states used 5 ft (1524 mm) gauge. Following the American Civil War , trade between the South and North grew and the Break Of Gauge became a major economic nuisance. After considerable debate and planning, most of the southern rail network was converted from 5 ft (1524 mm) gauge to 4 ft 9 in (1448 mm) gauge, then the standard of the Pennsylvania Railroad , over two remarkable days beginning on May 31 , 1886 . The final conversion to standard gauge took place gradually as track was maintained. In modern uses certain isolated occurences of non-standard guages can still be found, such as the Bay Area Rapid Transit system in the San Francisco Bay Area using 5 ft 6 in (1676 mm) gauge.

Russian Empire

In the nineteenth century, Russia chose a broader gauge. It is widely believed that the choice was made for military reasons, to prevent potential invaders from using the Russian rail system. Others point out that no clear standard had emerged by 1842 . Engineer Pavel Melnikov hired George Washington Whistler , a prominent American railroad engineer (and father of the artist James McNeill Whistler ), to be a consultant on the building of Russia's first major railroad, the Moscow – St Petersburg line. The selection of 1.5 m gauge was recommended by German and Austrian engineers (but not retained), it was ''not'' the same as the 5 ft (1524 mm) gauge which was in common use in the southern United States at the time. Now Russia and most of the former Russian Empire, including the Baltic State s, Ukraine , Belarus , the Caucasian and Central Asian republics, and Mongolia , have the official Russian measurement of 1520 mm, 4 mm narrower than 5 ft (1524 mm), though Rolling Stock of both gauges is interchangeable in practice.

= Finland

Finland, which was a Grand Duchy under Russia in the 19th century, uses 5 ft (1524 mm) gauge. Upon gaining independence in 1917, much thought was given to converting to standard gauge, but nothing came of it.

Iberian Peninsula

The main railway networks of Spain and Portugal were originally constructed to gauges of six Castilian Feet and five Portuguese Feet . Later, following adoption of the Metric System , these two gauges were defined as 1674 mm (5 ft 5.9 in) and 1665 mm (5 ft 5.55 in) respectively. The gauges were sufficiently close to allow inter-operation of trains, and in recent years both have been adjusted to a common Iberic Gauge of 1668 mm. Since the beginning of the 1990 s, however, new High-speed passenger lines in Spain have been built to the international standard gauge of 1435 mm, since it is intended that these lines will eventually cross the French border and link to the European high-speed network. Although the 22 km from Tardienta to Huesca (part of a branch from the Madrid to Barcelona high-speed line) have been reconstructed as mixed Iberic and standard gauge (i.e. with Three Running-rails ), in general the interface between the two gauges in Spain is dealt with by means of gauge-changing installations, which can adjust the gauge of appropriately designed rolling stock on the move.

British Empire

= Ireland

Ireland and Northern Ireland use 1600 mm gauge.

= Australia

In the 19th century, Australia's then three mainland states originally adopted standard gauge, but due to political differences a break of gauge 30 years in the future was created. After instigating a change to 5 ft 3 inch (1600 mm) agreed to by all, New South Wales reverted back to standard gauge while Victoria and South Australia stayed with 5 ft 3 in (1600 mm) gauge. At least 3 incompatible rail gauges are currently in use throughout Australia, and there is little prospect of full unification, though the main Interstate Routes are now standard gauge.

= Canada

In had until 1873 a 5ft 6in (1676 mm) gauge track.

= Hong Kong

In Hong Kong, the Mass Transit Railway uses a gauge of 1432 mm, which is 3 mm narrower than standard gauge. These trains can run on standard gauge only at low speeds. A new railway line across the Hong Kong-Zhuhai-Macau Bridge , an extension to the 1432 mm gauge Tung Chung Line , is a future option, but one which would require solving the problem of the 3 mm difference. This 3 mm difference should cause no more "problems" than the 4 mm difference causes between Russia and Finland, as mentioned above.

Asia

On independence from Britain , Bangladesh , India , Pakistan and Sri Lanka inherited a diversity of rail gauges, of which 1676 mm was predominant. Indian Railways has adopted Project unigauge, which seeks to systematically convert most of Indian Railways' narrower gauge railways to the 1676 mm.

Afghanistan is in an interesting position, because it is at the crossroads of Asia and is virtually without railways. Should it decide to build any, the choice of gauge will be complicated by its being surrounded by three different gauges (1435 mm, 1520 mm, 1676 mm) in four "gauge oceans" ? Iran to the west uses standard gauge, as does China to the east; to the south, Pakistan uses 1676 mm gauge, while to the north, the central Asian republics of Turkmenia , Uzbekistan , and Tajikistan use 1520 mm gauge.

South America

Argentina and Chile have 1676 mm lines. Brazil has 1600 mm lines.
Argentina and Peru also have 1435 mm lines.

Narrow Gauge

In many areas a much narrower gauge was chosen. While Narrow Gauge generally cannot handle as much tonnage, it is less costly to construct, particularly in mountainous regions. Plantations such as for sugar cane and bananas are appropriately served by Narrow Gauge lines such as 2 ft (610 mm), as there is little through traffic to any broader gauge main line systems.

British Empire

= Australia

Queensland , Tasmania , Western Australia and parts of South Australia adopted narrow gauge 3 ft 6 in (1067 mm) to cover greater distances at lower costs. Most industrial Railways are built to 2ft gauge. At least 3 incompatible rail gauges are currently in use throughout Australia , and there is little prospect of unification.

= Canada

The islands of Prince Edward Island (narrow gauge then mixed or dual gauge until 1930, standard gauge until abandonment) and Newfoundland which previously had railways, used a narrow gauge. The province of New Brunswick also had narrow gauge until the 1880s, after which standard gauge prevailed. In all these cases the narrow gauge was 3ft 6in (1067 mm). The White Pass And Yukon Railroad has a 3ft 0in (914 mm) gauge.

= New Zealand

New Zealand adopted Narrow Gauge 3 ft 6 in (1067 mm) due to the need to cross mountainous terrain in the country's interior. This terrain has necessitated a number of complicated engineering feats, notably the Raurimu Spiral . There are 1787 bridges and 150 tunnels in less than 4,000 km of track. Around 500 km of this track has been Electrified .

Asia

= Southeast Asia

The railways of Southeast Asia, including Vietnam , Cambodia , Laos , Thailand , Myanmar and Malaysia are predominantly metre-gauge (1000 mm). The proposed ASEAN Railway would be a standard-gauge or dual-gauge, using both metre and standard gauge regional railway network, linking Singapore , at the southern tip of the Malay Peninsula, through the Association Of Southeast Asian Nations region Malaysia , Thailand , Laos and Vietnam to the standard-gauge railway network of the People's Republic Of China . Indonesia 's railways are predominantly 1067 mm.

= Japan

Japan's railways are built to 3 ft 6 in (1067 mm) gauge. Japan's High-speed Shinkansen , or bullet trains are built to standard gauge for greater stability, which has caused some difficulties integrating high-speed and conventional passenger railway services.

= Taiwan

Taiwan, which was ruled by Japan from 1895 to 1945, has several 1067 mm lines, although its Taiwan High Speed Rail (HSR) line will also be standard gauge.

Africa

The railways of South Africa and many other African countries, including Angola , Botswana , Congo , Ghana , Mozambique , Namibia , Nigeria , Zambia and Zimbabwe , use 1067 mm gauge, which is sometimes referred to as Cape gauge. Kenya and Tanzania have meter gauge (1000 mm) lines.

South America

Argentina , Bolivia , Brazil and Chile have meter gauge (1000 mm) lines. Colombia and Peru have 914 mm lines.

DUAL GAUGE AND ADJUSTABLE AXLES

Dual gauge allows trains of different gauges to share the same right of way. This can save considerable expense compared to using separate tracks for each gauge. There can, however, be many difficulties and speed restrictions. If the difference between the two gauges is enough, three-rail dual-gauge is possible (say 1435 mm and 1067 mm), but if the difference is not enough, four-rail dual-gauge is necessary (say 1067 mm and 1000 mm). Dual gauge helps the conversion from one gauge to another. Dual-gauge rail lines are used in sections of the railway networks of Switzerland , Australia , Argentina , Brazil , North Korea , Tunisia and Vietnam .

Africa

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Rail Gauge