what is gauge in railway

In railway transport, gauge refers to the distance between the two rails of a railway track. It is essential for ensuring that all vehicles on a rail network have wheelsets that are compatible with the track gauge. The most common track gauge is the standard gauge, which has a distance of 1,435 mm (4 ft 8+1/2 in) between the inside edges of the rails. This standard gauge is widely used around the world, with about 55% of the world's railways using it. Different track gauges exist worldwide, and gauge differences can present a barrier to wider operation on railway networks. In the early days of rail travel, there was no universal standard for track gauges, and many engineers, private companies, and countries would simply build tracks to their designs. However, the adoption of a standard gauge has allowed for interconnectivity and interoperability of railway systems