The Dun Mountain Railway was a privately owned and operated 3 ft narrow gauge, 21.5 km (13.4 mi) long horse-drawn tramway from chromite mines in the vicinity of Duppa Lode on the eastern slopes of Wooded Peak to Nelson port in the Tasman District of New Zealand's South Island. It operated from 3 February 1862 to 30 May 1901, with the last mineral traffic on the incline section operated in January 1866.

Three foot gauge railways have a track gauge of 3 ft or 1 yard. This gauge is a narrow gauge and is generally found throughout North, Central, and South America. In Ireland, many secondary and industrial lines were built to 3 ft gauge, and it is the dominant gauge on the Isle of Man, where it is known as the Manx Standard Gauge. Modern 3 ft gauge railways are most commonly found in isolated mountainous areas, on small islands, or in large-scale amusement parks and theme parks. This gauge is also popular in model railroading, and model prototypes of these railways have been made by several model train brands around the world, such as Accucraft Trains (US), Aristo-Craft Trains (US), Bachmann Industries, Delton Locomotive Works (US), LGB (Germany), and PIKO (Germany).