Four foot ten inch gauge railways
A broad-gauge railway is a railway with a track gauge broader than the 1,435 mm (4 ft 8 1⁄2 in) standard-gauge railways.
Broad gauge was first used in Great Britain in Scotland for two short, isolated lines, the Dundee and Arbroath Railway (1836-1847) and the Arbroath and Forfar Railway (1838- ). Both the lines were built in 5 ft 6 in (1,676 mm). Both the lines were subsequently converted to standard gauge and connected to the emerging Scottish rail network.
The Great Western Railway, was designed by Isambard Kingdom Brunel, in 1838, with a gauge of 7 ft 1⁄4 in (2,140 mm), and retained this gauge until 1892. Some harbours also used railways of this gauge for construction and maintenance. These included Portland Harbour and Holyhead Breakwater, which used a locomotive for working sidings. As it was not connected to the national network, this broad-gauge operation continued until the locomotive wore out in 1913. The gauge initially proposed by Brunel was 7 ft (2,134 mm) exactly but this was soon increased by 1⁄4 in (6 mm) to accommodate clearance problems identified during early testing.
While the parliament of the United Kingdom of Great Britain and Ireland was initially prepared to authorise lines built to the broad gauge of 7 ft 1⁄4 in (2,140 mm), it was eventually rejected by the Gauge Commission in favour of all railways in the British Isles being built to standard gauge of 4 ft 8 1⁄2 in (1,435 mm), this being the gauge with the greatest mileage. Ireland, using the same criteria, was allocated a different standard gauge, the Irish gauge, of 5 ft 3 in (1,600 mm) which is also used in the Australian states of South Australia and Victoria. Broad-gauge lines in Britain were gradually converted to dual gauge or standard gauge from 1864, and finally the last of Brunel's broad gauge was converted over a single weekend in 1892.
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