Variable gauge

Overview

Variable gauge axles help solve the problem of a break-of-gauge without having to resort to dual gauge tracks or transshipment. Systems allow the adjustment between two gauges. No designs supporting more than two gauges are used.

Systems

There are several variable gauge axle systems:

Compatibility

The variable gauge systems are not themselves all compatible. Only the SUW 2000 and Rafil Type V systems are interoperable.

In 2009, at Roda de Barà near Tarragona, a Unichanger capable of handle four different VGA systems was under development.

International traffic

VGA is particularly important with international railway traffic because gauge changes tend to occur more often at international borders.

Speed

The maximum speed of the trains equipped with the different technologies vary. Only CAF and Talgo produce high-speed VGA, allowing speeds up to 250 km/h.

Gauge changer

A gauge changer is a device which forces the gauge adjustment in the wheels. Designs consist of a pair of running rails that gradually vary in width between the two gauges, combined with other rails and levers to unlock, move, support and re-lock the adjustable axles.

In the Spanish Talgo-RD system, a constant spray of water is used to lubricate the metal surfaces, to reduce heat and wear. A Talgo-RD gauge changer is 20 metres long and 6 metres wide.

Operation

Variable gauge multiple units, or a train including a variable gauge locomotive (e.g. Talgo 250) and rolling stock, may drive straight across a gauge changer. Normally the locomotive will not be able to change gauge, meaning that it must move out of the way whilst the remainder of the train itself passes through. On the opposite side, a new locomotive of the other gauge will couple to the train.

A train (or an individual car) can be pushed halfway across the gauge-changer, uncoupled, and then (once far enough across) coupled to the new locomotive and pulled the rest of the way. A long length of wire-rope with hooks on the end means that the process can be asynchronous, with the rope used to bridge across the length of the gauge changer (to temporarily couple the arriving cars and receiving locomotive, although without braking control from the locomotive to the train vehicles).

On long-distance trains in Spain and night trains crossing from Spain into France, the arriving locomotive stops just short of the gauge changer, uncouples and moves into a short siding out of the way. Gravity then moves the train through the gauge changer at a controlled low speed. The new locomotive is coupled onto the front only after the full train has finished passing through the changer.

Australia

In 1933, as many as 140 inventions were offered to Australia railways to overcome the breaks of gauge between the different states. None was accepted. About 20 of these devices were adjustable wheels/axles of some kind or another, which may be analogous to the modern VGA. VGA systems were mostly intended for Broad Gauge and Standard Gauge lines.

Canada

Variable gauge axles were used for a while on the Grand Trunk Railway in the 1860s in Canada to connect 5 ft 6 in (1,676 mm) and 4 ft 8 ¹⁄₂ in (1,435 mm) standard gauge without transshipment. Five-hundred vehicles were fitted with "adjustable gauge trucks" but following heavy day-in, day-out use the system proved unsatisfactory, particularly in cold and snowy weather. The system used telescoping axles with wide hubs that allowed the wheels to be squeezed or stretched apart through a gauge-changer, after holding pins had been manually released.

Railway operations over the Niagara Bridge were also complicated.

China

Finland/Sweden

In 1999, a gauge-changer was installed at Tornio at the Finnish end of the dual-gauge section between Haparanda and Tornio, for use with variable gauge freight wagons. The Tornio gauge changer is a Rafil design from Germany; a similar Talgo-RD gauge changer at the Haparanda end used to exist, but was removed as it required de-icing in winter.

Train ferry traffic operated by SeaRail and arriving from Germany and Sweden by sea used bogie exchange facilities in the Port of Turku.

Germany–Russia

(See Spain)

Japan

The "Gauge Change Train" is a project started in Japan in the 1990s to investigate the feasibility of producing an electric multiple unit (EMU) train capable of operating both the 1,435 mm (4 ft 8 ¹⁄₂ in) Shinkansen high-speed network at 270–300 km/h and the original 1,067 mm (3 ft 6 in) network at 130–140 km/h. See U.S. Patent 5,816,170.

The first-generation train was tested from 1998 to 2006, including on the US High-speed Test Track in 2002. The second-generation train, intended to run at a maximum speed of 270 km/h (170 mph), was test-run in various locations in Japan between 2006 and 2013. A third-generation train has been undergoing reliability trials since 2014 in preparation for potential introduction to service on the planned Kyushu Shinkansen extension to Nagasaki.

Poland

Poland has SUW 2000 gauge changers installed on international lines to Lithuania and Ukraine used for daily night-trains and some freight transport.

Spain

Spain is the largest user of variable gauge systems. Much of the Iberian Peninsula has a different gauge from the rest of Europe. The older lines use 1,668 mm (5 ft 5 ²¹⁄₃₂ in), with new high-speed railway lines and connections to France using 1,435 mm (4 ft 8 ¹⁄₂ in) standard gauge. There are also significant lengths of 1,000 mm (3 ft 3 ³⁄₈ in) lines. Two gauge changes are installed on lines to France and at all entrances/exits leading between the high-speed network and older lines.

In February 2004, RENFE placed orders for:

Switzerland

Variable gauge axles are going to be implemented on the Montreux–Gstaad–Zweisimmen–Spiez–Interlaken line. Trains will automatically switch from 1,000 mm (3 ft 3 ³⁄₈ in) to 1,435 mm (4 ft 8 ¹⁄₂ in) at Zweisimmen. A trial bogie has been built and tested. It has no axles which allow the bogie half frames holding the wheels on both sides to slide sideways to each other.

Ukraine

As part of a joint bid for the 2012 European Football cup with Poland VGA trains would be introduced across their border.

United Kingdom

John Fowler mentions in 1886 at attempt by the GWR to develop a "telescopical" axle.

Trams ran between Leeds (1,435 mm (4 ft 8 ¹⁄₂ in) gauge) and Bradford (4 ft (1,219 mm) gauge) following a successful trial in 1906 using Bradford tram car number 124. The system was later patented by – GB 8959 of 1906. This system was improved again in patent GB 19655 of 1909 by introducing a locking system acting on the wheel and axle rather than just the wheel rim. This provided a more effective grip where the wheel was free to move along the axle.

Time taken

In VGA, the train is pulled through the "adjuster" at about 10 km/h (2.77 m/s) without any need to uncouple the wagons or disconnect (and test) the brake equipment.

Spares

VGA always has the exact number of wheels of each gauge and they are always at hand, whereas with truck exchange, there must be a complete set of trucks of the right gauge and with wheels of the same diameter at the depot.

Truck exchange needs a stock of spare trucks of each gauge, which need to be shunted as required. If there is an influx of traffic one might run out of trucks of the other gauge. Depending on the sophistication of the exchange facility, the cars may need to be uncoupled for the truck exchange to take place.

Locomotives

Steam locomotive are generally not gauge convertible on-the-fly. While diesel locomotives can be truck exchanged, this is not normally done owing to the complexity in the reconnection of cables and hoses. In Australia, some locomotives are transferred between gauges. The transfer might happen every few months, but not for an individual trip.

By 2004, variable gauge electric passenger locomotives were available from Talgo. It is not clear if variable gauge freight locomotives are available.

Electric

Weight

History