Question: what is the difference between a standard gauge and a narrow gauge?
Answer: A narrow-gauge railway (narrow-gauge railroad in the US) is a railway with a track gauge narrower than standard 1,435 mm (4 ft 8 1⁄2 in). Most narrow-gauge railways are between 600 mm (1 ft 11 5⁄8 in) and 1,067 mm (3 ft 6 in). ... Narrow-gauge trams, particularly metre-gauge, are common in Europe.