Editing Dual gauge (section)

==Alternatives==
[[File:Schema rollbocks trucks.PNG|thumb|[[Rollbock]]s compared to [[transporter wagon]]s]]

[[File: Australian National Railways 5-pack freight cars and container loader, Islington freight terminal, 1985.jpg |thumb|250px|Standardised [[Intermodal container|containers]] have revolutionised rail, road and sea [[freight transport]]. Although mechanisation has sped up handling, moving containers from one train to another because of different rail gauges is costly and inefficient.]]

Transfer of freight and passengers between different gauges does not necessarily involve dual-gauge track: there may simply be two tracks that approach either side of a platform without overlapping. In Australia, 13 break-of-gauge stations existed by 1945 as a result of longstanding interstate rivalries: three different gauges had persisted since the 1850s and the five mainland state capitals were not linked by standard gauge until 1995.<ref>{{cite book|title=Australian Railwayman: from cadet engineer to railways commissioner |last=Fitch |first=Ronald J. |date=2006 |location=Dural, New South Wales |publisher=Rosenberg Publishing Pty Ltd |page=168 |isbn=1877058483 }}</ref> Huge costs and long delays were imposed by [[Transshipment|trans-shipment]] of freight at break-of-gauge stations, whether manually, by gantry crane or by wheelset or bogie exchange.<ref name=haul/>{{rp|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&nbsp;million tonnes of freight.<ref>{{cite book |last=Laird |first=Philip |date=2001 |title=Back on track: re-thinking transport policy in Australia and New Zealand |publisher=University of New South Wales Press |location=Sydney |isbn=086840411X |page=187}}</ref>

To cost and inefficiency was added, in the case of passengers, considerable inconvenience. In 1896, at [[Albury railway station|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".<ref>{{cite web |url= http://www.online-literature.com/twain/following-the-equator/14/ |title=  Following the Equator |first= Mark |last= Twain |date= 2020 |website= The Literature Network|access-date= 27 May 2020 }}</ref>

In some locations, an alternative to building long lengths of dual-gauge track has been to change the wheels on [[railroad car|rolling stock]], either by dropping and changing wheelsets from [[Train wheel|four-wheeled]] vehicles or exchanging bogies (US: trucks) under eight-wheeled vehicles. With this arrangement, a short length of dual-gauge track is only needed within the facility. A benefit is that the contents of fully loaded cars are not disturbed. The scheme was first adopted on the French–Spanish border and in Poland. It introduces delay into transit times compared with dual-gauge operation, but is much quicker than trans-shipping: when introduced in 1962 in Melbourne, Australia, on the route between Sydney and Adelaide, the freight handling time per train dropped from five days to less than two. The process involved disconnecting the [[Railway brake|brake rigging]] and [[bogie]] [[List of railroad truck parts#Center pin|centre pins]] have to be disconnected before the vehicle is lifted and new bogies are wheeled underneath.<ref name=buckland>{{cite journal | last=Buckland |first=J.L.  |date=October 1962 |title=Bogie changing extends the benefits of standard-gauge |journal=[[Australian Railway History|Australian Railway Historical Society Bulletin]] |volume=XIII |issue=300 |pages=161–162 |issn=0005-0105 }}</ref>{{refn|group=note|At that time, each transfer took 20 minutes; inspection and marshalling took up the remaining time.<ref name=buckland/> In 1982, each of two shifts of 18 men exchanged an average of 66 bogies per day; in comparison, 100 men would have been needed to transfer the same amount of freight wagon to wagon.<ref>{{cite book |author=Lee, Robert |title=The Railways of Victoria 1854–2004 |publisher=Melbourne University Publishing Ltd |year=2007 |isbn= 978-0-522-85134-2 |page=224}}</ref>}}

In Europe, a similar principle embodies low-profile, small-wheeled [[transporter wagon]]s, which carry vehicles built for one gauge on a line with a different gauge. 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.<ref>{{cite AV media|date=2015 |title=Harzquerbahn 2015 – Güterverkehr zwischen Unterberg und Nordhausen |trans-title=Freight traffic between Unterberg and Nordhausen |language=|url=https://www.youtube.com/watch?v=6CBdZdcGpmI |access-date=3 November 2022 |publisher=Schmalspurbahn-Fans }}</ref> The entire train is converted in minutes at a slow walking pace, each rollbock being automatically matched to its wheelset from underneath.{{refn|group=note|The [[Ramsey car-transfer apparatus|principle]] of attaching narrow-gauge bogies from underneath in this manner had been patented by Robert Henry Ramsey in 1872, in the United States.<ref>{{cite web|url=https://www.midcontinent.org/rollingstock/builders/ramseys_cartruck.htm |title=Ramsey's car truck shifting apparatus |author=<!--Not stated-->|date=2007 |website=Mid-Continent Railway Museum |access-date=3 November 2022}}</ref>}}

A further variant is "[[Train on Train|train on train]]", in which an entire narrow-gauge train is carried on standard-gauge [[flatcar]]s on which continuous rail has been fitted.<ref>{{cite book| title=Uniform railway gauge| first=Eric| last=Harding| publisher=Lothian Publishing| year=1958| page=14}}</ref><ref>{{cite book| title=Tales from a Railway Odyssey| authorlink=Keith Smith (engineer)| first=Keith A.| last=Smith| page=114}}</ref><ref>{{cite journal |last=Buckland |first=J.L. |date=December 1955 |title=The "pick-a-back" train |journal=[[Australian Railway History|Australian Railway Historical Society Bulletin]] |volume=VI |issue=218 |pages=157–162 |issn=0005-0105 }}</ref>

Differences in gauge are also accommodated by [[variable gauge|gauge-adjustable wheelsets]], which {{As of|2022|lc=yes}} were installed under some passenger vehicles on international links between Spain and France, Sweden and Finland, Poland and Lithuania, and Poland and Ukraine. In Spain, change-over facilities are extensive, since although {{Track gauge|1668mm|comma=off}} track predominates, and high-speed lines are laid to {{Track gauge|1435mm|comma=off}} [[Standard-gauge railway|standard gauge]], there are many lines with narrower gauges ({{Track gauge|1000mm|comma=off}} [[Metre-gauge railway|metre gauge]] and others).<ref>{{cite book|url=https://www.vialibre-ffe.com/pdf/Track_gauge_changeover.pdf|title=Automatic track gauge changeover for trains in Spain|first=Alberto García|last=Álvarez|publisher=Fundación de los Ferrocarriles Españoles|edition=4|date=2010|isbn=978-84-89649-56-9|page=7}}</ref>