A railroad is described as a broad gauge when its track is wider than the 56.5-inch (143.5-cm) standard gauge developed in England in the early 1800s. The additional width between the rails can be small or large; the 58-inch (147.32-cm) track used in parts of the United States during the 19th century and the 84.25-inch (214-cm) lines of England’s Great Western Railway at about the same time are both considered to have been broad gauges. Some of the major North American broad gauge railroads ran on track measuring 60 inches (152.4 cm), 66 inches (167.64 cm) or 72 inches (182.88 cm). Today, though, only a few streetcar or light rail lines there are wider than standard. Adolf Hitler envisioned a 118.11-inch (300-cm) gauge system as an ultimate railroad connecting key points in an expanded post-World War II Germany, but no track for the proposed operation was ever built.
Broad gauge has fared better in some parts of the world, including the 60-inch (152.4-cm) track used today in Finland and in countries of the former Soviet Union. Portugal runs trains on 66.5-inch (166.5 cm) track, and the track in Ireland is 63 inches (160 cm) wide. Spain uses 65.7-inch (166.8-cm), track and railroads in India, Iran and Argentina are barely wider at 66 inches (167.6 cm).
Lines in some parts of Australia were built to 63-inch (160-cm) gauge and later converted to standard, but broad gauge tracks theoretically offer significant advantages to railroads and to customers. Its wider track permits the use of larger equipment, and that means more freight or passengers can be carried. It also means that passengers ride in spacious cars with better accommodations, but there are some disadvantages.
For passengers, a broad gauge railroad effectively limits the distance covered without changing trains, because although there is some tolerance for gauges that are only slightly different, equipment often cannot be transferred to a standard gauge line or even to another, different broad gauge route. The situation is worse for freight, where the virtual impossibility of interchanging cars with standard gauge railroads requires increased handling of loads and added expenses. Railroads have dealt with that problem by temporarily changing the gauge of rolling stock for interchange or by laying dual gauge and even triple gauge track.
Broad gauge locomotives built for those lines were in some cases equipped with offset couplers. This would allow narrower freight and passenger cars to be handled on a multi-gauge track. Other locomotives have been designed so that comparatively easy conversions would enable their operation on various tracks from broad to narrow gauge as required.
