While the predominant railway network in India is Broad Gauge (BG) with a width of 1.676 metres, the rapid rail transport system in Delhi, the high-speed rail line between Mumbai and Ahmedabad, and more than a score of metro rail systems in parts of the country are coming up on Standard Gauge (SG) of 1.435 m width.
The gauge debate began in the 1870s when the British introduced Metre Gauge of 1,000 mm in India after starting with BG in 1853. Following extensive deliberations, a uni-gauge policy was launched in the 1990s and progressively, barring a few difficult sections, all the routes were converted to BG.
However, by the turn of the 20th century, SG came to be first employed on metro rail networks following a Cabinet resolution which was based on a set of recommendations from a group of empowered Ministers, who left the decision on the choice of gauge to individual State governments.
