Broad gauge

Broad gauge refers to a railway with a gauge (distance between the rails) greater than the standard gauge of 1435mm (4ft 8.5in).

In England the Great Western Railway pioneered broad gauge from 1838 with a gauge of 7ft 0.25in (2140mm), and retained this gauge into the 1890s. Many countries have broad gauge railways: Ireland and some parts of Australia have a gauge of 1600mm (5ft 3in). Russia, the other former Soviet Republics and Finland use the 1524mm gauge inherited from the Imperial Russia. The Baltic States have received funding from the European Union for rebuilding their railways with the standard gauge. Portugal uses 1665mm and Spanish Renfe 1674mm. In India a gauge of 1676mm (5ft 6in) is widespread. This is also used by the Bay Area Rapid Transit system of San Francisco, California.

While Russia and Spain chose broad gauge to make railborne invasion by its enemies that much more difficult, most non-standard broad gauges get in the way of interoperability of railway networks.On the GWR, 2140mm gauge was supposed to allow for high speed, but GWR had difficulty with locomotive design in the early years (which threw away much of their advantage), and rapid advances in permant way and suspension technology saw standard gauge speeds approach broad gauge speeds within a decade or two in any case. On the 1600mm and 1676mm gauges, the extra width allowed for bigger inside cylinders and greater power, a problem solvable by outside cylinders on standard gauge. On BART, the wider gauge is supposed to prevent lightweight trains getting blown over by the wind.

Where trains find a different gauge such as the Spanish-French border or the Russian-Chinese one, several engineering solutions have been in place. Examples are emptying the wagons and moving the upper part to another chassis, or multigauge[?] boogies[?]

See also standard gauge, narrow gauge.