Regulating the Gauge of Railways Act 1846
An Act for regulating the Gauge of Railways was enacted by the British Parliament on 18 August 1846. It mandated standard gauges of 4 ft 8 1⁄2 in for Great Britain, and 5 ft 3 in for Ireland. The 7 ft (2,134 mm) gauge, designed by I.K. Brunel when engineering the Great Western Railway, was limited to the south west of England and Wales. The law stated that these railways "shall be constructed on the Gauge of Seven Feet". This isolation ultimately marked the end for Brunel's 7 ft broad gauge system.