The second is metre gauge which is 1,000mm (3ft 3⅜in). This is said to have been introduced by Richard Southwell Bourke, the sixth Earl of Mayo, popular as Lord Mayo, the fourth Viceroy of India. Metre gauge is said to be based on calculations to allow four persons to sit comfortably abreast—it would have been 3ft 3in except that there was then a push to move to the metric system and so the gauge became 1m. The first metre gauge line was built in 1872 in Delhi.
