Track gauge in Italy

Historically, Italy had two unusual dominant track gauges which were legally defined depending on the terrain encountered. The gauge of was used for the national Italian rail network and was very similar to the  standard gauge commonly used elsewhere in the world.

Since the 1930s, the gauge has been adopted as the standard and gradually replaced the  track gauge. Thus, in Italy, only a few older tram systems, such as the Milanese tramway network, remain equipped with.

The other popular gauge, a narrow gauge, was defined at and is very similar to the metre gauge –  – commonly used in many other parts of Europe and thus came to be known as "the Italian metre gauge".

Historical legal definitions of 1879
Italian law has defined its track gauges in terms of the distance between the centres of each rail, 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 were, , measured between the rail centres, which correspond to and  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.

gauge railways
The following systems survive today: Outside Italy, the Madrid Metro also uses this gauge.
 * Orvieto Funicular
 * Milan tram network
 * Turin tram network
 * Rome tram network
 * Naples tram network

or standard gauge railways
The Italian standard gauge railway system has a total length of 24227 km of which active lines are 16723 km. The network is recently growing with the construction of the new high-speed rail network.

Italian narrow gauge railways
In Italy, track gauges of, , , , and  are or were present.

The aforementioned "Italian metre gauge" was also used in the former Italian colonies of Eritrea (Eritrean Railway), Libya (Italian Libya Railways), and Somalia (Mogadishu-Villabruzzi Railway).