Dual gauge

Pairs of rails that become too wide or narrow in gauge will cause derailments, especially if in excess of normal gauge-widening on curves.

[5][6]: 74–75  The problem is worsened when there is a disparity between the capacity of locomotives and vehicles on the two gauges: typically, one broad-gauge trainload needs three narrow-gauge trains to carry.

Construction and operation of triple-gauge track and its signalling, however, involves immense cost and disruption, and is undertaken when no other alternative is available.

[17] Huge costs and long delays were imposed by trans-shipment of freight at break-of-gauge stations, whether manually, by gantry crane or by wheelset or bogie exchange.

[6]: 67  During World War II, breaks of gauge in Australia added immense difficulty to the war effort by needing extra locomotives and rolling stock, and more than 1600 service personnel and a large pool of civilians, at transfer points for an annual average transfer of about 1.8 million tonnes of freight.

In 1896, at Albury station on the Sydney–Melbourne railway, famed American writer Samuel Clemens (Mark Twain) had to change trains in the middle of a "biting-cold" night in 1896 and there formed his pungent view of "the paralysis of intellect that gave that idea birth".

A variant is the rollbock (Rollböcke in German), used under two-axle standard-gauge vehicles: each wheelset is carried on a small four-wheeled narrow-gauge trolley.

[22] The entire train is converted in minutes at a slow walking pace, each rollbock being automatically matched to its wheelset from underneath.

[27] In Victoria, there are sections of 1600 mm (5 ft 3 in) and 1435 mm (4 ft 8+1⁄2 in) dual-gauge track between Southern Cross station and West Footscray, Sunshine and Newport, Albion and Jacana, North Geelong and Gheringhap, Maryborough and Dunolly, and in various goods yards and industrial sidings.

In 1900, in South Australia, a three-rail dual-gauge system was proposed in order to avoid a break of gauge.

Dual-gauge track is also used from the triangle at Woodbridge to Cockburn Junction, then to Kwinana on one branch and North Fremantle on the other.

Passenger trains use the dual-gauge section of the Beenleigh railway line running parallel to the electric suburban narrow gauge of the Queensland Rail city network over the Merivale Bridge into platforms 2 and 3 at Roma Street Station.

This is used by standard gauge interstate New South Wales TrainLink XPT services to Sydney.

In 2004, in Jindřichův Hradec at a switch where a dual gauge railway bifurcates, a Junák express from Plzeň to Brno derailed due to a signalling error.

The Stuttgart Straßenbahn Museum operates 1000 mm (3 ft 3+3⁄8 in) gauge trams on weekends and special occasions.

Two lines share a tunnel section between the Mülheim (Ruhr) Hauptbahnhof and Schloss Broich then diverge at street level.

The track was owned by the Nederlandsch-Indische Spoorweg Maatschappij, a private company, which in 1867 had built the 1435 mm (4 ft 8+1⁄2 in) gauge line.

The third rail was installed to allow passengers and goods travelling over the 1067 mm (3 ft 6 in) gauge Staatsspoorweg (state railway) a direct connection.

At a later date, the government constructed new tracks to allow greater capacity and higher speeds.

Ireland's Ulster Railway underwent a gauge conversion from 1880mm to the new Irish standard of 1600 mm (5 ft 3 in).

Dual gauge is used where the 1435 mm (4 ft 8+1⁄2 in) Shinkansen (bullet train) lines join the main network.

For the 1939 centennial celebration, an exact replica of the country's first locomotive "De Arend" was built using the original blueprints.

[34] Similar arrangements exist on the approach to Kaliningrad, where 1435 mm (4 ft 8+1⁄2 in) track extends from the Polish border with some sections of dual gauge.

In 2009, Adif called for tenders for the installation of a third rail for standard-gauge trains on the 22 km (14 mi) between Castellbisbal and the Can Tunis freight terminal in Barcelona.

At each end of the dual-gauge section are yards with standard and Finnish gauge areas to allow for trans-shipment.

A ″non-stop″ scheme (albeit with a pause to change locomotives) on the Montreux-Interlaken route was inaugurated in December 2022.

This is in part due to the Austro-Hungarian heritage of the Zakarpattia Oblast, but also has military and political importance, as it allows standard-gauge trains to run between Romania and Slovakia by bypassing Hungary, otherwise impossible due to the break-of -gauge between the Russian-gauge network of Ukraine and standard-gauge networks of Romania and Slovakia.

A short section of broad and standard gauge is at the Great Western Society site at Didcot.

The port authority in Derry, Northern Ireland, used a dual-gauge line in a street-level network to transfer freight.

Previously, in its yard at Mount Union, Pennsylvania, the East Broad Top Railroad and Coal Company used dual-gauge tracks.