How Wide Is A Narrow Gauge Railway Line?

Railways come in a variety of different gauges. Narrow gauge lines are oftentimes utilized in mountainous terrain, however, today, narrow gauge lines are typically used in tourist operations.

How wide is a narrow gauge railway line? 3 ft 6 in (1,067 mm). Most narrow gauge lines conform to these measurements, however, a few lines are even narrower, measuring 1 ft 11 58 in (600 mm).

Narrow gauge lines are interesting to both the enthusiast and the lay observer, and harness many qualities not found on full sized railways.

According to George W. Hilton’s blog entry on, track gauge is considered to be the length on the inside of the inside vertical sections of the head of the rail. Interestingly, in Victorian England, Isambard Kingdom Brunel deemed the standard gauge of 4 ft 8 1/2 in. insufficient for his trains on the under construction, Great Western Railway, which would travel at speeds between 50-60 mph. Thus, his 7 ft gauge was designated broad gauge, and today’s standard gauge was designated narrow gauge.

However, as the 4 ft 8 1/2 in. gauge was adopted throughout Britain and other parts of the world, it was designated as the standard gauge. Broad gauge in the modern day is considered to be 5 ft 3 in., and is utilized throughout Ireland. Any gauge less than 4 ft 8 1/2 inches is considered narrow or metre gauge.

One of the Ffestiniog Railway’s narrow gauge steam locomotives, makes its way to the terminus at Porthmadog. The Ffestiniog Railway utilizes a gauge of 1 ft 11 1/2 in. (597m). Matt Spencer Photo

A railway is considered narrow gauge if its width is less than 4 ft 8 1/2 in. and is usually between 1 ft 5/8 in.(600mm) and 3 ft 6 in (1,067mm). Narrow gauge lines are oftentimes built as a cheaper alternative to a standard or a broad gauge line. Narrow gauge railway utilize lighter rail, tighter curves, and less expensive infrastructure such as bridges and tunnels.

Narrow gauge railways are also useful in confined spaces, such as in a mine or mountainous terrain, where the topography constitutes a tighter loading gauge, as there is a small area to build a right-of-way. This gave the narrow gauge railway increasing popularity with mining companies, as the reductions of cost and the ability to build within a certain confined space was paramount. Furthermore, narrow gauge railway’s are popular to reach destinations where potential ridership does not warrant the expense of a standard gauge railway, such as small towns and villages, and mountainous communities.

While standard gauge is utilized in most countries, various countries utilize narrow or metre gauge tracks, such as New Zealand, parts of Australia, Indonesia, and Thailand, just to name a few. Interestingly, the narrow gauge railway dates back to the 16th century in Bohemia, where early railways were utilized in mines. These primitive railways were operated by men pushing carts through the mines, which similar to most early railways, led to a canal.

The narrow gauge railway became increasingly popular upon the genesis of the steam locomotive, as steam locomotive technology progressed, narrow gauge steam locomotive could be seen working mines, once commanded by equestrian power. Interestingly, the first steam locomotive tested by engineer Richard Trevithick in South Wales was narrow gauge. Furthermore, Salamanca, the world’s first commercially successful steam locomotive, operated on the 4 ft Middeton and Leeds Railway.

Narrow gauge railways were oftentimes well suited for various construction projects such as bridges and tunnels, as they could be quickly and inexpensively constructed, and equally as effortless to remove.


Although narrow gauge lines are oftentimes effective in a variety of different circumstances, they suffer from incompatibility with other standard gauge railways, further complicating the process of transshipment. Thus, when these lines join one another, a break of gauge will oftentimes be implemented. Break-of-gauge occurs when two gauges utilize the same stretch of track, such as on the Great Western Railway in the United Kingdom, whereas standard gauge and broad gauge were utilized on the same right-of-way until the late 19th century. Although this has been proven to be an effective solution, it is extremely expensive, and difficult to maintain, and oftentimes causes congestion on the railway.

The popular Durrango and Silverton Railway in Colorado are one of the few railways in the world that have employed the continuous use of steam power.

In addition to break of gauge, bogie or truck exchanges may be utilized. Bogie exchange is often a time consuming and tedious process, as the bogie of each piece of rolling stock must be removed in exchange for a bogie that is of appropriate gauge. This is an interesting tactic that is mostly reserved for rolling stock such as passenger and freight cars, however, locomotives may be given new bogies if enough time is allotted. However, oftentimes, locomotives are replaced with those of the correct gauge.

A rollblock is another popular method of dealing with varying gauges. Rollbacks were originally utilized in Switzerland and Spain, interestingly for the latter, the devices were utilized to transport broad gauge rolling stock over standard gauge railways. The rollblock device is rolled under each wagon by the installation of narrow gauge tracks within the standard gauge, and picks up each truck or bogie, eliminating the need for a bogie exchange. Rollblocks are less time consuming and more cost effective than the traditional bogie exchange.

Further drawbacks of narrow gauge railways lie within their construction, as due to their low curve radius, narrow gauge railways cannot operate as fast as standard or broad gauge trains. In many countries, narrow gauge railways have been converted to standard gauge. Conversion to standard gauge is performed strictly out of convenience of maintenance and equipment, as due to the tight curve radius, track speed cannot be increased.

Additional setbacks lie within the locomotives and rolling stock on a narrow gauge line, whereas the locomotives could be more expensive due to extensive modifications to bring them up to par with narrow gauge track. Furthermore, regarding steam locomotives, railways have concluded that a larger boiler on a steam engine performs at a lower average cost, therefore, narrow gauge steamers are less efficient than standard gauge due to the implementation of a smaller boiler.(Hilton)

New Zealand’s state supported Kiwirail operates heavy rail service over its narrow gauge network. Kiwirail has experienced much success in its investment in narrow gauge.

Although narrow gauge lines have their drawbacks when utilized for heavy railway haulage, there have been several instances where these railways have experienced success. For example, in Queensland, Australia, South Africa, and New Zealand, narrow gauge railways have found sustainability. In South Africa’s narrow gauge Sishen-Saldanha Railway, freight trains spanning hundreds of cars traverse the tracks of the narrow gauge line located on the county’s western cape. These trains primarily haul iron ore between mines in the northern cape, with various ports on the western cape.

In Queensland, high speed tilting trains operate over narrow gauge track, which consequently, was the world’s first railway to utilize narrow gauge track on a mainline railway. Although a variety of trains operate over this portion of track, the most notable is the “tilt train”, which utilizes Shinkansen traction motor technology, and holds the Australian railway speed record, traveling 130 mph (210 km/h) in 1999.

New Zealand has also found great success with narrow gauge railway’s, most notably, their Tranz Scenic, Tranz Metro, and Transdev Auckland routes, which have all garnered much success over the course of their operations, with Kiwi Rail, New Zealand’s major carrier.

Related Questions

Why are train tracks a certain width? Interestingly, the width of train tracks dates back to the early Romans, as the width of the standard gauge, 4 ft 8 1/2 inches, was the width needed to accommodate their chariots. While constructing tramways to transport coal from mines to canals, these measurements were taken into account as the tramways utilized equestrian power. 

What is the width of a standard gauge railway in the UK? In the UK, standard gauge is 4 ft 8 1/2 inches. Utilizing standard gauge on commercial railways was the suggestion of early railway pioneer George Stephenson, as it was the gauge he was most accustomed to in the mines. 

What is the difference between metre gauge and broad gauge? Metre gauge measures in width at 1000m or one meter (3 ft 3/8 in.). While broad gauge could range anywhere between 5 ft and 5 ft 6 in. Metre gauge is utilized in various countries, however, main line operations of this gauge are only utilized in various South American countries, Spain, eastern Europe, Africa, and New Zealand. 




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