Variable gauge: Wikis


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A variable gauge system (Spanish: cambio de ancho) allows railway vehicles in a train to travel across a break of gauge caused by two railway networks with differing track rail gauges.

For through-operation, a train must be equipped with special bogies holding variable gauge wheelsets containing a variable gauge axle. The gauge is altered by driving the train through a gauge changer or gauge changing facility. As the train passes through the gauge changer, the wheels are unlocked, moved closer together, or further apart, and are then re-locked. Installed variable gauge systems exist within the internal network of Spain, and are installed on international links between Spain/France, Finland/Sweden, Poland/Lithuania and Poland/Ukraine.

Several alternatives exist, including transferring the cargo, replacing individual wheels and axles, bogie exchange, transporter wagons or the simple transshipment of the goods or passengers.

Alternative names include Gauge Adjustable Wheelsets (GAW), Automatic Track Gauge Changeover System (ATGCS/TGCS), Rolling Stock Re-Gauging System (RSRS), Rail Gauge Adjustment System (RGAS), Shifting wheelset,[1] Variable Gauge Rolling Truck,[2] track gauge change and track change wheelset



Variable gauge axles help solve the problem of a break of gauge without having to resort to dual gauge tracks or transshipment. Current systems allow the adjustment between two present gauges. No designs supporting more than two gauges are currently used.[3]



There are several variable gauge axle systems:


The various current variable gauge systems are not themselves all compatible. Only the SUW 2000 and Rafil Type V systems are interoperable.[4]

In 2009, at Roda de Bara near Tarragona, a Unichanger capable of handle four different VGA systems was under development.[19]

International traffic

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

Gauge changer

The gauge changer (Spanish: cambiadores de anchos) 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 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.


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 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, wagon, or carriage 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 wagons and receiving locomotive).

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. A built-in diesel propulsion system on board the rake of coaches then moves the train carriages through the gauge changer at a controlled low speed. The new locomotive is coupled onto the front only after the full train has finished passed through the changer under its own power.



In the early 20th Century as many as 124 inventions were offered to Australia railway to overcome the breaks of gauge between the different states. None were accepted. [20]


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+12 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. 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.[21][22][23]

Railway operations over the Niagara Bridge were also complicated.[24]


  • A Patent with diagram [25]


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.[26] 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[27] as it required de-icing in winter.[28]

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


Gauge Change Trains are under development to allow running of Electric Multiple Unit trains on 1,435 mm (4 ft 8+12 in) high-speed network at 300 km/h and off onto the smaller 1,067 mm (3 ft 6 in) network at reduced speeds.[29][30] See US patent 5816170.[31][32]

One of trains was tested on the US HS Test Track in 2002.[33][34]


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

  • November 2008 - High Speed trainset for Cadiz to Warsaw.[35]
  • Since 14 December 2003, VGA trains were introduced between Krakow (Poland) and Kiev (Ukraine) instead of bogie exchange.[36] VGA saves about 3 hours compared to bogie exchange. Gauges involved are 1,435 mm (4 ft 8+12 in) and 1,520 mm (4 ft 11+56 in).


Spain is the largest user of variable gauges 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+23 in), with new high-speed railway lines and connections to France using 1,435 mm (4 ft 8+12 in) standard gauge. There are also significant lengths of 1,000 mm (3 ft 3+38 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:

  • Forty-five CAF/Alstom 25 kV AC/3 kV DC, variable gauge EMUs for 250 km/h regional services, between October 2006 and May 2009 (€580 million)
  • Twenty-six 25 kV AC variable gauge trains for 250 km/h long-distance services using two Bombardier power cars and Talgo Series VII trailer cars (€370 million) Gauges involved are 1,435 mm (4 ft 8+12 in) and 1,668 mm (5 ft 5+23 in).
  • Olmedo to Medina del Campo in Valladolid, Spanish test track. [37]
  • November 2008 - High Speed trainset for Cadiz to Warsaw.[35]
  • July 2009 - Talgo 250 supplied with Voith Turbo SZH-692 gauge change final drives.[38]


Variable gauges axes are going to be implemented on the Montreux-Interlaken-Lucerne line trains between Montreux and Interlaken will switch from 1,000 mm (3 ft 3+38 in) to 1,435 mm (4 ft 8+12 in) at Zweisimmen.[39]

Sudan / Egypt

The difference between 1,067 mm (3 ft 6 in) and 1,435 mm (4 ft 8+12 in) is 368 mm which is relatively large compared to standard gauge/broad gauge VGA. The axles have to move further, requiring a longer gauge change facility, and there is less room between the wheels for the VGA equipment, the disc brakes, and any traction motors.[40][41]

United Kingdom

Trams ran between Leeds (1435 mm gauge) and Bradford (1220 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.[42]

Comparison with bogie exchange

Time taken

In VGA, the train is pulled through the "adjuster" at about 10 km/h [43] (2.77 m/s) without any need to uncouple the wagons or disconnect (and test) the brake equipment.


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

Bogie exchange needs a stock of spare bogies of each gauge, which need to be shunted around as required. If there is a tide of traffic one might run out of bogies of the other gauge. Depending on the sophistication of the exchange depot, the wagons may need to be uncoupled for the bogie exchange to take place.


Steam locomotive are generally not gauge convertible on-the-fly. While diesel locomotives can be bogie exchanged,[44] this is not normally done owing to the complexity in the reconnection of cables and hoses. In Australia, some locos 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.[45][46][47] It is not clear if variable gauge freight locomotives are available.


  • L-9202 is an experimental high speed Bo-Bo dual voltage (3 kV DC/25 kV AC) VGA locomotive. [48]
  • Talgo 250 locomotives were also planned to haul dual-voltage variable-gauge trainsets from Montpellier 200 km from the border to Barcelona and Madrid. Two Talgo 250 power cars haul 11 passenger trailer cars.[49][50]
  • EMU [51]


  • A gauge adjustable bogie and wheelsets weigh a total of about one ton/tonne more than a conventional bogie and normally have to use disc brakes, which are harder to cool.[35][52]


  • 1915. C. W. Prosser.[53]
  • 1921. C. R. Prosser. Argus Friday 8 July 1921 [54]
  • 1922. Grieve Argus 19 July 1922 [55]

See also


  1. ^
  2. ^
  3. ^
  4. ^ a b c d e f Kanclerz, Miroslaw (2007-10-09). "Study on European Automatic Track Gauge Changeover Systems (ATGCS)". Gdansk: UIC. Retrieved 2008-12-07. "Variable gauge systems: SUW 2000, Poland; DBAG/Rafil Type V, Germany; CAF BRAVA, Spain; Talgo RD, Spain; Japan RTRI; Korea KRRI [..] DB Rafil Type V and PKP SUW 2000 are technically compatible and thereby ‘interoperable’"  
  5. ^ Talgo Date=2008-09-04
  6. ^ BRAVA
  7. ^
  8. ^ La Vie du Rail, No. 1415, 4 November 1973, ÉCARTEMENTS VARIABLES: L' "ESSIEU MIRACLE" EST-IL NÉ DANS LE CANTON DE VAUD? [1] in French or [2] in English)
  9. ^ Janes World Railways 2002-2003 p165.
  10. ^ Variable-Gauge Wagon Wheelsets | International Railway Journal
  11. ^ Schwartze, Matthias. "Gauge change system could help ease movement between countries". Rail International/Live Engineer. Retrieved 2008-09-17. "The DB AG/Rafil Type V change gauge wheel set consists of a wheel set shaft and two axially displaceable solid wheels, which are joint to the shaft by a locking system. The solid wheel has been derived from the well-proved solid wheel of the 004 type of DB AG."  
  12. ^
  13. ^ Science Links Japan | Development of Variable Gauge Bogie
  14. ^
  15. ^ [3]
  16. ^
  17. ^ Railway Gazette International December 2008 p944
  18. ^ Prose Website
  19. ^ Railway Gazette International July 2009, p20
  20. ^
  21. ^ "Introduction". Niagara Rails. Retrieved 2008-09-17. "two mechanical solutions were tried: the GWR used a dual gauge system requiring a third rail, and the GTR used adjustable gauge trucks. However neither method proved satisfactory, and full conversion to standard gauge became necessary"  
  22. ^ "Break of Gauge at Prescott Junction". Bytown Railway Society, Branchline, June 2003. Colin Churcher's railway pages. 2003-06. Retrieved 2008-09-03. "The scheme selected was patented by C.D. Tisdale of East Boston, Massachusetts, with the first patent having been issued in March 1863. Special wheels with extra-large hubs were fitted with key wedges. The axles were notched so that the wheels could be set at standard or 5 -foot 6-inch gauge. The keys were locked in place by a long safety pin and giant rubber bands. The position of the wheel was shifted by a gradually diverging or converging track. In the shift from broad to standard, the keys would be loosened and removed at one end of the tapering track, workmen in a 4-foot-deep pit removed the keys from below the train. A long shed was built over the pits to protect the workmen. With the keys out, the train was slowly pushed down the track, and the wheels-would be forced inward as the train moved along the converging rails. Once at the end, the workers would reinsert and lock the wedges and the train could go on its way. The change could be done in five to ten minutes. When shifting to broad gauge, a third rail set inside the tapering track pushed the wheel out to the wider gauge. Shifting stations were located at Point St. Charles, Montreal, and Sarnia, Ontario. The plan was first tried in November 1863, yet no serious consideration was given to it until early 1868. The tests proved so promising that by late in the following year two hundred adjustable-gauge cars were running between Chicago and Boston via the Michigan Central, the Grand Trunk, the Vermont Central, and several connecting lines in New England. The problems of the northern east-west route seemed to have been resolved, and three hundred more cars were ordered by National Despatch. [...] his disruptive and costly conversion might have been avoided had the changeable-gauge trucks worked as well as advertised. Problems obviously had developed. The keyway grooves were said to weaken the axles. Misgivings over the safety of the telescoping axles were voiced as early as 1846, long before the Grand Trunk test. Considerable skepticism was expressed as to the reliability of the workmen charged with loosening and tightening so many wheels day in and day out.""  
  23. ^
  24. ^
  25. ^
  26. ^ "VR Annual Report 1998" (PDF). VR Group. 1998. Retrieved 2008-09-17. "Traffic between Tornio and Haaparanta continued to decline slightly. Measures were taken to boost the volume on this line by speeding up border crossing formalities. Development of a new track gauge changing machine made further progress and testing will be started in Tornio in the early spring of 1999. This machine will raise traffic volumes between Finland and Scandinavia."  
  27. ^ Thorsten Büker (2004-12). "border lines Sweden - Finland". Retrieved 2008-09-17. "In 2002 through workings by suitable wagons had been involved in cooperation of Finnish VR, Green Cargo and Nordwaggon. A Gauge-changer of German design "Rafil" was installed at Tornia [sic], a Talgo-type gauge changer at Haparanda. This one was already taken out of use."  
  28. ^ Lars-Åke Josefsson (2007-03-15). "A bridge between differences in infrastructure" (PDF). Automatic track gauge technique. Banverket (Swedish National Rail Administration). pp. p.14 & p.18. Retrieved 2008-09-17. "Trials with systems with automatic track gauge change technique have been going on at the border between Sweden and Finland since 1997 during severe winter conditions. Two different systems, the spanish Talgo system and the german Rafil system, have been tested. We have decided to go on with the Rafil system. [...] 14 bogies has been bought. Commercial traffic has been going on since October 2005."  
  29. ^ Science Links Japan | Gauge Change Train. Development of Monitor System of Gauge Change Train
  30. ^
  31. ^ Japan Railway & Transport Review - see picture page 6
  32. ^
  33. ^
  34. ^
  35. ^ a b c Railway Gazette International November 2008, p 881
  36. ^ Enthusiast's Guide to Travelling the Railways of Europe, Special notes
  37. ^ "GIF develops dual-gauge track". International Railway Journal. 2002-03. Retrieved 2008-12-07. "A new test track, which opened in December 2001, is being used to help develop and test the dual-gauge concept. The 14.4 km track between Olmedo and Medina del Campo in Valladolid province, includes 10 km of tangent track (part of the old Segovia-Medina line, which has been out of service since 1993), a gauge-changing facility, workshops, and a technical building for the interlocking. ... The test track is not yet electrified, so initial tests, which started in January, were conducted using a Talgo XXI diesel train. Tests include running through turnouts and crossings at a maximum of 242 km/h on plain track and 110 km/h on deviations."  
  38. ^
  39. ^
  40. ^
  41. ^
  42. ^
  43. ^
  44. ^ Motive Power
  45. ^
  46. ^
  47. ^ L-9202 Bo-Bo Dual Voltage Double Ended Locomotive by TRAV-CA
  48. ^
  49. ^
  50. ^
  51. ^
  52. ^
  53. ^
  54. ^
  55. ^

External links


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