Standard Gauge

The standard gauge (also named the Stephenson gauge after George Stephenson, or normal gauge) is a widely-used track gauge. Approximately 60% of the world's existing railway lines are built to this gauge (see the list of countries that use the standard gauge). Except for Russia and Finland, all high-speed lines have been built to this gauge.

The distance between the inside edges of the rails of standard gauge track is usually called 1,435 mm but in the United States it is still called 4 ft 8½ in.