Narrow gauge railway
The next natural "grouping" of narrow gauge railways covers the range from 600 mm (1 ft 11 5 ⁄ 8 in) to just below 900 mm (2 ft 11 1 ⁄ 2 in), although the majority are between 610 mm (2 ft) and 762 mm (2 ft 6 in).These lightweight lines can be built at a substantial cost saving over medium or standard gauge railways, but are generally restricted in their carrying capacity.