Gauge: 5ft 3in and 3ft (915mm)
Derry / Londonderry in Northern island had two miles of quays, with mixed gauge 5ft 3in and 3ft railway lines, connecting the four railway stations. Apart from a short period, the lines were for freight traffic only.
In 1854 the Londonderry Port & Harbour Commissioners were established to manage the port and oversee its expansion. The Commissioners were also given full control of the waterways from the city to the mouth of Lough Foyle, allowing for strategic planning of the port.
By the 1920s the port had two miles of quays, with warehouses, stationary and mobile cranes, and with railways along the entire length connected to the four rail systems serving the city. The port had its own railway yard, under the control of the Londonderry Port & Harbour Commissioners (LPHC). This railway had connections to the other railways in Derry; The Great Northern and the Northern Counties Committee, both of which were 5ft 3in gauge, and thanks to a length of dual gauge, the County Donegal Railways Joint Committee and Londonderry & Lough Swilly Railway, which were 3ft. Wagons could be shunted across the Foyle by way of the lower deck of the Craigavon Bridge, with dual gauge turntables at each end.
Originally worked by horses, steam locomotives were introduced from 1872. These were 5ft 3in gauge, fitted with dual couplings to work both 5ft 3in and 3ft gauge wagons. Two of the LPHC locomotives survived into preservation- No. 1, which is at the Ulster Folk & Transport Museum in Cultra, and No. 3, which is owned by the Railway Preservation Society of Ireland at Whitehead.
The railway system closed on 31st August 1962.