Minimum-gauge railways have a gauge of most commonly 15 in, 400 mm, 16 in, 18 in, 19 in, 500 mm or 20 in. The notion of minimum-gauge railways was originally developed by estate railways and the French company of Decauville for light railways, trench railways, mining, and farming applications.
Two locomotives of the Whiskey River Railway, an attraction at Little Amerricka in Marshall, Wisconsin
In rail transport, track gauge is the distance between the two rails of a railway track. All vehicles on a rail network must have wheelsets that are compatible with the track gauge. Since many different track gauges exist worldwide, gauge differences often present a barrier to wider operation on railway networks.
Fish-belly cast-iron rails from the Cromford and High Peak Railway
An early Stephenson locomotive
Triple gauge, from left: 1,435 mm (4 ft 8+1⁄2 in), 1,000 mm (3 ft 3+3⁄8 in), and 600 mm (1 ft 11+5⁄8 in), on display at the China Railway Museum in Beijing
A cartoon depicting the horrors of goods transfer at the break of gauge at Gloucester in 1843