Narrow gauge railway

History

The earliest recorded railway is shown in the De re metallica of 1556, which shows a mine in Bohemia with a railway of about 2 ft (610 mm) gauge. During the 16th century, railways were mainly restricted to hand-pushed narrow-gauge lines in mines throughout Europe. During the 17th century, mine railways were extended to provide transportation above ground. These lines were industrial, connecting mines with nearby transportation points, usually canals or other waterways. These railways were usually built to the same narrow gauge as the mine railways from which they developed.

The world's first steam locomotive on rails, built in 1802 by Richard Trevithick for the Coalbrookdale Company, ran on a 3 ft (914 mm) plateway. During the 1820s and 1830s, a number of industrial narrow-gauge railways in the United Kingdom used steam locomotives. In 1842, the first narrow-gauge steam locomotive outside the UK was built for the 1,100 mm (3 ft 7 ⁵⁄₁₆ in) gauge Antwerp-Ghent Railway in Belgium. The first use of steam locomotives on a public, passenger-carrying narrow-gauge railway came in 1865 when the Ffestiniog Railway introduced its passenger service, after receiving its first locomotives two years prior.

Historically, many narrow-gauge railways were built as part of specific industrial enterprises and were primarily industrial railways rather than general carriers. Some common uses for these industrial narrow-gauge railways were mining, logging, construction, tunnelling, quarrying, and the conveying of agricultural products. Extensive narrow-gauge networks were constructed in many parts of the world for these purposes. For example, mountain logging operations in the 19th century often used narrow-gauge railways to transport logs from mill sites to market. Significant sugarcane railways still operate in Cuba, Fiji, Java, the Philippines, and Queensland. Narrow-gauge railway equipment remains in common use for the construction of tunnels.

Extensive narrow-gauge railway systems served the front-line trenches of both sides in World War I. They were a short-lived military application, and after the end of the war, the surplus equipment from these created a small boom in narrow gauge railway building in Europe.

Advantages

Narrow-gauge railways usually cost less to build because they are usually lighter in construction, using smaller cars and locomotives (smaller loading gauge), as well as smaller bridges, smaller tunnels (smaller structure gauge) and tighter curves. Narrow gauge is thus often used in mountainous terrain, where the savings in civil engineering work can be substantial. It is also used in sparsely populated areas where the potential demand is too low for broader gauge railways to be economically viable. This is the case in some of Australia and most of Southern Africa, where extremely poor soils have led to population densities too low for standard gauge to be viable.

For temporary railways that will be removed after short-term use, such as for construction, the logging industry, the mining industry, or large-scale construction projects, especially in confined spaces, such as the Channel Tunnel, a narrow-gauge railway is substantially cheaper and easier to install and remove. The use of such railways has almost vanished due to the capabilities of modern trucks.

In many countries, narrow gauge railways were built as "feeder" or "branch" lines to feed traffic to more important standard gauge lines, due to their lower construction costs. The choice was often not between a narrow-gauge railway and a standard gauge one, but between a narrow-gauge railway and none at all.

Interchangability

Narrow-gauge railways cannot interchange rolling stock such as freight and passenger cars freely with the standard gauge or broad gauge railways with which they link, and the transfers of passengers and freight require time-consuming manual labour or substantial capital expenditure. Some bulk commodities, such as coal, ore, and gravel, can be mechanically transshipped, but this still incurs time penalties and the equipment required for the transfer is often complex to maintain.

If rail lines with other gauges coexist in the network, in times of peak demand, it is very difficult to move rolling stock to where it is needed when a break of gauge exists, so enough rolling stock must be available to meet a narrow-gauge railways' own peak demand, which might be much more than needed when compared to a network with only one gauge, and the surplus equipment generates no cash flow during periods of low demand. In regions where narrow gauge forms only a small part of the rail network, like the Sakhalin railway in Soviet Russia, extra cost is needed to specifically design, produce or import narrow-gauge equipment which increases the cost of narrow-gauge vehicle compared to regular vehicles.

Growth potential

Another problem commonly faced by narrow-gauge railways was that they lack the physical space to grow: their cheap construction meant they were engineered only for their initial traffic demands. While a standard or broad gauge railway can be more easily be upgraded to handle heavier, faster traffic, many narrow-gauge railways were impractical to improve. Speeds and loads hauled could not increase, so traffic density was significantly limited. In the case of Queensland, Australia, the Queensland Rail passenger network has nearly reached its capacity due to the narrow gauge and an ever-increasing population, as such, new lines are to be built, thus negating the original cost savings. In Japan, a few narrow gauge lines have been upgraded to standard gauge mini-shinkansen to allow through service by standard gauge high speed vehicles, but due to the alignment of those lines and minimum curve radius of those lines, the maximum speed of those through service is still the same as the original narrow-gauge rail line.

If a narrow-gauge line is built to higher standard like the proposed Super Tokkyū concept in Japan, its problem can be reduced.

Interchangability

Solutions to interchangeability problems of transshipment are bogie exchange between cars, a rollbock system, variable gauge, dual gauge, or even gauge conversion. European standard gauge trains normally use buffers and chain couplers, which do not allow such tight curves, a main reason to have narrow gauge. Therefore, narrow-gauge trains normally use other couplers, which makes bogie exchange meaningless.

Alternatively, a rail network comprises only narrow-gauge network could also eliminate the interchangeability problem.

Growth potential

If narrow-gauge rails are designed with potential growth in mind, or with same standard as standard gauge rails, then the obstacles to be faced in future growth of those rail lines would be similar to other rail gauge.

For those lines constructed to a lower standard, speed can be increased via nimerous methods including realigning rail lines to increase the minimum curve radius, reducing the number of intersections, or introducing tilting trains to improve the speed of trains running on those lines.

Successful railways

The heavy duty 3 ft 6 in (1,067 mm) narrow-gauge railways in Australia (e.g. Queensland), South Africa, and New Zealand show that if the track is built to a heavy-duty standard, performance almost as good as a standard gauge line is possible. Some 200-car trains operate on the Sishen-Saldanha railway in South Africa, and high-speed tilt-trains run in Queensland. Another example of a heavy-duty narrow-gauge line is EFVM in Brazil. 1,000 mm (3 ft 3 ³⁄₈ in) gauge, it has over-100-pound rail (100 lb/yd or 49.6 kg/m) and a loading gauge almost as large as US nonexcess-height lines. It has multiple 4,000 hp (3,000 kW) locomotives and 200+ car trains. In South Africa and New Zealand, the loading gauge is similar to the restricted British loading gauge, and in New Zealand some British Rail Mark 2 carriages have been rebuilt with new bogies for use by Tranz Scenic (Wellington-Palmerston North service), Tranz Metro (Wellington-Masterton service), and Transdev Auckland (Auckland suburban services).

Fastest trains

The reduced stability of narrow gauge means its trains cannot run at the same high speeds as on broader gauges. For instance, if a curve with standard gauge rail can allow speed up to 145 km/h (90 mph), the same curve with narrow-gauge rail can only allow speed up to 130 km/h (81 mph).

In Japan and Queensland, recent permanent way improvements have allowed trains on 3 ft 6 in (1,067 mm) gauge tracks to run at 160 km/h (99 mph) and faster. Queensland Rail's tilt train is currently the fastest train in Australia and the fastest 3 ft 6 in (1,067 mm) gauge train in the world, setting a record at 210 km/h. The current speed record for 3 ft 6 in (1,067 mm) narrow-gauge rail is 245km/h, set in South Africa, 1978.

A special 2 ft (610 mm) gauge railcar was built for the Otavi Mining and Railway Company with a design speed of 137 km/h.

Curve radius is also important for high speeds: narrow-gauge railways allow sharper curves, which limits the speed at which a vehicle can safely proceed along the track.

Costs

Many engineers considered the cost of a railway varies with some power of the gauge, so the narrower gauge the cheaper it might be. This applied also to different narrow gauges, such as a proposed line in Papua using either 610 mm (2 ft) or 1,067 mm (3 ft 6 in).

Nomenclature

In general, a narrow-gauge railway has a track gauge less than standard gauge. However, due to historical and local circumstances, the definition of a narrow-gauge railway can be different.

Gauges used

Many narrow gauges are in use or formerly used between 15 in (381 mm) gauge and 1,435 mm (4 ft 8 ¹⁄₂ in) gauge. They fall into several broad categories:

Scotch gauge

Scotch gauge was the name given to a 4 ft 6 in (1,372 mm) track gauge, that was adopted by early 19th-century railways mainly in the Lanarkshire area of Scotland. Also 4 ft 6 ¹⁄₂ in (1,384 mm) lines were constructed. Both gauges were eventually converted to standard gauge.

Four foot and 1200 mm gauges

Three foot, six inch gauge

1,067 mm (3 ft 6 in) between the inside of the rail heads. The name and classification varies throughout the world. It has installations of around 112,000 kilometres (70,000 mi).

Similar gauges are:

Metre gauge and Italian metre gauge

Metre gauge is the system of narrow-gauge railways and tramways with a track gauge of 1,000 mm (3 ft 3 ³⁄₈ in). It has installations of around 95,000 km (59,000 mi).

As a result of Italian law, track gauges in Italy were defined from the centres of each rail, rather than the inside edges of the rails. This gauge was measured 950 mm (3 ft 1 ³⁄₈ in) between the edges of the rails and is known as Italian metre gauge

Three foot, 900 mm, and Swedish three foot (891 mm) gauge

Three foot gauge railways have a track gauge of 3 ft (914 mm) and are generally found throughout North and South America, as well as Ireland and the Isle of Man.

900 mm (2 ft 11 ⁷⁄₁₆ in) gauge railways are generally found in Europe. Swedish three foot gauge railways (891 mm (2 ft 11 ³⁄₃₂ in)) can only be found in Sweden.

750 mm (2 ft 5 1⁄2 in), Bosnian gauge, and two foot six inch gauge

750 mm (2 ft 5 ¹⁄₂ in) and Bosnian gauge (760 mm (2 ft 5 ¹⁵⁄₁₆ in)) railways are predominantly found in Russia and Eastern Europe.

The Imperial 2 ft 6 in (762 mm) gauge railways were generally constructed in the former British colonies, such as the Kelani Valley Line (now 5 ft 6 in (1,676 mm)) in Sri Lanka.

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. The majority of these lines were built in mountainous areas, the majority for carrying mineral traffic from mines to ports or standard gauge railways.

Two foot (610 mm), 600 mm, and similar gauges

Gauges: 2 ft (610 mm), 1 ft 11 ³⁄₄ in (603 mm), 600 mm (1 ft 11 ⁵⁄₈ in), and 1 ft 11 ¹⁄₂ in (597 mm)

Minimum gauge

Gauges below 1 ft 11 ¹⁄₂ in (597 mm) were rare, but did exist. In Britain, Sir Arthur Heywood developed 15 in (381 mm) gauge estate railways, while in France Decauville produced a range of industrial railways running on 500 mm (19 ³⁄₄ in) and 400 mm (15 ³⁄₄ in) tracks, most commonly in restricted environments such as underground mine railways, parks and farms. Several 18 in (457 mm) gauge railways were built in Britain to serve ammunition depots and other military facilities, particularly during World War I.