A narrow-gauge railway is one on which the gauge (the distance between the rails) is less than “standard gauge”, the gauge used by British Rail which is four feet eight and a half inches. Some of the first uses of the these “light railways” were quarrying, contractors work and passenger carrying. Small steam locomotives were used on such lines with considerable success and were still in use on British narrow-gauge systems until the 1960s. From the turn of the century, the development and refinement of the internal combustion engine made the installation of these new power units in locomotives a practical possibility. One of the first successful uses of these locos was on the supply lines in the First World War. Hundreds of two foot gauge petrol locos were used in France and Germany and proved their suitability and advantages over steam power.
Such was the ease with which these railways could be constructed, maintained and modified, that all sorts of industries developed their own internal systems. At one time the vast majority of brickworks, peat works and water works had their own narrow gauge railway, many of them using ex-military equipment obtained as war surplus at a knock-down price. In the early 1930s the first practical diesel locomotives were introduced and soon became the norm. Battery locomotives were also introduced, being particularly successful in underground applications such as mines.
Since the 1960s, the introduction of more modern and less labour-intensive transportation systems, such as conveyors, has almost entirely replaced the narrow-gauge railway in most industries. Some railways are still in use in coal mines and on peat works, but even these applications are on the decline.