Great Britain, 1748

In 1748, the Wylam waggonway was built to a 5 ft (1,524 mm) gauge for the shipment of coal from Wylam to Lemington down the River Tyne.^[4]

In 1839, the Eastern Counties Railway was constructed. In 1840, the Northern and Eastern Railway was built. In 1844, both lines were converted to 1,435 mm (4 ft 8+1⁄2 in) standard gauge. In 1903, the East Hill Cliff Railway, a funicular, was opened.

United States, 1827

In 1827, Horatio Allen, the chief engineer of the South Carolina Canal and Rail Road Company, prescribed the usage of 5 ft (1,524 mm) gauge. Many other railroads in the Southern United States adopted this gauge. The presence of several distinct gauges was a major disadvantage to the Confederate States of America during the American Civil War. In 1886, when around 11,500 miles (18,500 km) of 5 ft gauge track existed in the United States, almost all of the railroads using that gauge were converted to 4 ft 9 in (1,448 mm), the gauge then used by the Pennsylvania Railroad.^[5]

Russian Empire, 1842

In 1837, the first railway built in Russia was a 6 ft (1,829 mm) gauge, 17 km long experimental line connecting Saint Petersburg with Tsarskoye Selo and Pavlovsk. The choice of gauge was influenced by Brunel's Great Western Railway which used 7 ft (2,134 mm). The Tsarskoye Selo railway's success proved that a larger gauge could be viable for railways isolated from the extant 1,435 mm (4 ft 8+1⁄2 in) gauge Western European network.^[6][7]

In 1840, work started on the second railway in the Russian Empire, the Warsaw–Vienna railway in Congress Poland. It was a 1,435 mm (4 ft 8+1⁄2 in) standard gauge, with the express intention of allowing through-freight trains into Austria-Hungary.^[6][7]

The modern Russian railway network solidified around the Saint Petersburg–Moscow railway, built in 1842. There, the Tsar established a committee to recommend technical standards for the building of Russia's first major railway. The team included devotees of Franz Anton von Gerstner, who pushed to continue the Tsarskoye Selo gauge, and engineer Pavel Melnikov and his consultant George Washington Whistler, a prominent American railway engineer. Whistler recommended 5 ft (1,524 mm) on the basis that it was cheaper to construct than 6 ft (1,829 mm) and cheaper to maintain than 1,435 mm (4 ft 8+1⁄2 in). His advice won over the Tsar.^[6][7]

At the time, questions of continuity with the European network did not arise. By the time difficulties arose in connecting the Prussian railroads to the Russian ones in Warsaw in the 1850s, it was too late to change.^[6]

A persistent myth holds that Imperial Russia chose a gauge broader than standard gauge for military reasons, namely to prevent potential invaders from using the rail system.^[8] The Russian military recognized as early as 1841 that operations to disrupt railway track did not depend on the gauge, and should instead focus on destroying bridges and tunnels.^[6][7] However, in both World Wars the break of gauge did pose some amount of obstacle to the invading Germans.

Panama, 1850

The Panama Canal Railway, first constructed in ca. 1850, was built in 5 ft (1,524 mm) gauge. During canal construction (1904–1914), this same gauge was chosen for both construction traffic, canal operating services along the quays, and the newly routed commercial cross-isthmus railway. In 2000 the gauge for the commercial parallel railway was changed to 1,435 mm (4 ft 8+1⁄2 in) to use standard gauge equipment. The original gauge was chosen under the influence of the pre-conversion southern United States railway companies. The electric manoeuvering locomotives along the locks (mules) still use the 5 ft gauge that was laid during canal construction.

Finland, 1862

The first rail line in Finland was opened in January 1862. As Finland was then the Grand Duchy of Finland, an autonomous state ruled in personal union by Imperial Russia where railways were also built to the (5 ft) broad track gauge of 1,524 mm (5 ft).^[14] However the railway systems were not connected until the bridge over the River Neva was built in 1913.^[15] Russian trains could not have run on Finnish tracks, because the Finnish loading gauge was narrower, until the connection was made and the Finnish structure gauge was widened.

Redefinitions

In the late 1960s the gauge was redefined to 1,520 mm (4 ft 11+27⁄32 in) in the Soviet Union.^[3] At the same time the tolerances were tightened. As the running gear (wheelsets) of the rolling stock remained unaltered, the result was an increased speed and stability.^[14] The conversion took place between 1970 and the beginning of the 1990s.^[14]

In Finland, the Finnish State Railways kept the original definition of 1,524 mm (5 ft), even though they also have tightened the tolerances in a similar way, but to a higher level.

After its independence from the Soviet Union in 1991, Estonia redefined its track gauge to 1,524 mm, to match Finland's gauge.^[16] The redefinition did not mean that all the railways in Estonia were changed immediately. It was more a rule change, so that all renovated old tracks and new railways would be constructed in 1,524 mm gauge from then on. (See Track gauge in Estonia.)

Tolerances

Finland allows its gauge to be 1,520–1,529 mm on first class lines (classes 1AA and 1A, speed 220–160 km/h).^[17]

If the rolling stock's tolerance is kept within certain limits, through running between 1,520 mm (4 ft 11+27⁄32 in) railways and Finnish 1,524 mm (5 ft) railways is allowed. Since both 1,520 and 1,524 mm tolerances overlap, the difference is negligible. The international high-speed Allegro's gauge between Helsinki and St. Petersburg was specified as 1,522 mm.^[18]

Loading gauge

The loading gauge, which defines the maximum height and width for railway vehicles and their loads, is larger for Russian gauge. This means that if a standard gauge railway, in Europe, is adapted for dual gauge, bridges must be rebuilt, double tracks must be placed further apart and the overhead wire must be raised. Or there must be restrictions on permitted rolling stock, which would restrict the benefit of such a railway. Dual gauge needs more width than single gauge. For double stacking on Russian gauge tracks, maximum height shall be 6.15 or 6.4 m (20 ft 2 in or 21 ft 0 in) above rails.

For standard gauge railways, double stacking maximum height shall be 6.15 m (20 ft 2 in). For Indian gauge railways, double stacking maximum height shall be 7.1 m (23 ft 4 in), and minimum overhead wiring height shall be 6.5 or 6.75 m (21 ft 4 in or 22 ft 2 in) above rails. Minimum overhead wiring height for double stacking, standard gauge railways shall be 6.5 m (21 ft 4 in), and Indian gauge railways shall be 7.45 m (24 ft 5 in) above rails, respectively. This would apply to Russia and Europe (or North America), rather than to Russia and China (or Iran).

Primary usage

The primary countries currently using the gauge of 5 ft or 1,520 mm, include:^[19]

Extended usage

Short sections of Russian or 5 ft gauge extend into Poland, eastern Slovakia, Sweden (at the Finnish border at Haparanda), and northern Afghanistan.^[20]

There is an approximately 150 km long section in Hungary in the Záhony logistics area close to the Ukrainian border.^[21]

Following renovations in 2014, a 32 km section of dual Standard/Russian gauge was installed between Tumangang and Rajin stations in North Korea.^[22]

The most western 1,520 mm gauge railway is the Polish LHS (Linia Hutnicza Szerokotorowa) from the Ukrainian border to the eastern end of the Upper Silesian Industrial Region.

Use in rapid transit and light rail systems

Although broad gauge is quite rare on lighter railways and street tramways worldwide, almost all tramways in the former USSR are broad gauge (according to terminology in use in these countries, gauges narrower than 1,520 mm (4 ft 11+27⁄32 in) are considered to be narrow). Many tramway networks initially built to narrow gauges (750 mm or 2 ft 5+1⁄2 in or 1,000 mm or 3 ft 3+3⁄8 in metre gauge) were converted to broad gauge. As of 2015, only a few out of more than sixty tram systems in Russia are not broad gauge: 1,000 mm in Kaliningrad and Pyatigorsk, 1,435 mm (4 ft 8+1⁄2 in) in Rostov-on-Don. There are two tram systems in and around Yevpatoria that use 1,000 mm (3 ft 3+3⁄8 in) gauge.^{[note 1]}

Finland's Helsinki trams and Latvia's Liepāja trams use 1,000 mm (3 ft 3+3⁄8 in). Estonia's Tallinn trams use similar 1,067 mm (3 ft 6 in). Warsaw's tramway system, constructed with 1525 mm gauge, was regauged to 1435 mm during post-WWII reconstruction.^[23] Tampere tramway, built in 2021, uses 1,435 mm (4 ft 8+1⁄2 in).

Underground urban rapid transit systems in the former USSR, like the Moscow Metro, Saint Petersburg Metro, Kyiv Metro and Yerevan Metro use Russian gauge (1,520 mm). Outside the former USSR, the Helsinki Metro in Finland that utilizes a unique track gauge of 1,522 mm, falls between the Russian gauge (1,520 mm) and broad gauge 1,524 mm.

Railways using 1,524 mm gauge

Railways using 1,520 mm gauge