Historically,Italy had two unusual dominanttrack gauges which were legally defined depending on the terrain encountered. The gauge of1,445 mm (4 ft 8+7⁄8 in) was used for the national Italian rail network and was very similar to the1,435 mm (4 ft 8+1⁄2 in)standard gauge commonly used elsewhere in the world.
Since the 1930s, the1,435 mm gauge has been adopted as the standard and gradually replaced the1,445 mm track gauge. Thus, in Italy, only a few older tram systems, such as theMilanese tramway network, remain equipped with1,445 mm.
The other popular gauge, anarrow gauge, was defined at950 mm (3 ft 1+3⁄8 in) and is very similar to themetre gauge –1,000 mm (3 ft 3+3⁄8 in) – commonly used in many other parts of Europe and thus came to be known as "the Italian metre gauge".
Italian law has defined its track gauges in terms of the distance between the centres of each rail,[1] rather than the inside edges of the rails, giving some unusual measurements. According to the law of 28 July 1879, the only legal gauges in Italy were1,500 mm (4 ft 11+1⁄16 in),1,000 mm (3 ft 3+3⁄8 in), measured between the rail centres, which correspond to1,445 mm (4 ft 8+7⁄8 in) and950 mm (3 ft 1+3⁄8 in) between the rail inside edges.
The narrower gauge has 1,000 mm between the centres of the rails, which explains the name Italian metre gauge, but it is 950 mm in gauge when measured from the inside of the rails, as gauges are normally measured in other countries.
A disadvantage of measuring from the centre of the rail is that the width of the rail varies and affects the gauge. It is easier and more reliable to measure from the inner edges of the rails.
The Italian standard gauge railway system has a total length[2] of 24,227 km (15,054 mi) of which active lines are 16,723 km (10,391 mi).[3] The network is recently growing with the construction of the newhigh-speed rail network.
In Italy, track gauges of1,100 mm (3 ft 7+5⁄16 in),1,000 mm (3 ft 3+3⁄8 in),950 mm (3 ft 1+3⁄8 in),850 mm (2 ft 9+15⁄32 in),760 mm (2 ft 5+15⁄16 in) and600 mm (1 ft 11+5⁄8 in) are or were present.
