Standard gauge
The standard gauge (also Stephenson gauge after George Stephenson, International gauge, or normal gauge) is a widely used railway track gauge. Approximately 55% of the lines in the world are this gauge (see the list of standard gauge usages). All high-speed rail lines (except those in Russia, Uzbekistan, India, and Finland) are standard gauge. The distance between the inside edges of the rails is defined to be 1,435 millimetres (4 ft 8 ⁄2 in) (except in the United States and Canada, where it is still defined in imperial units as 4 feet 8 ⁄2 inches (1,435.1 mm)). It is also called the UIC gauge or UIC track gauge, the European gauge in the EU and Russia, or uniform gauge in Queensland.