Lebar sepur ganda

Dalam teknik perkeretaapian, "'''lebar sepur'''" adalah jarak melintang antara permukaan bagian dalam kepala dua rel, yang untuk sebagian besar jalur kereta api adalah jumlah rel di tempat. Namun, terkadang "rel" perlu membawa kendaraan kereta api dengan roda yang disesuaikan dengan dua alat pengukur yang berbeda. Trek seperti itu digambarkan sebagai **pengukur ganda** - dicapai baik dengan penambahan rel ketiga, jika sesuai, atau dengan dua rel tambahan. Track ukuran ganda lebih mahal untuk dikonfigurasikan dengan sinyal dan dinding, dan untuk pemeliharaan, daripada dua track ukuran tunggal yang terpisah. Oleh karena itu, biasanya untuk membangun rel pengukur ganda atau **multi-ukuran** lainnya hanya jika diperlukan karena kurangnya ruang atau saat rel dari dua pengukur berbeda bertemu di "Halaman langsir" atau stasiun penumpang. Track pengukur ganda sejauh ini merupakan konfigurasi yang paling umum, tetapi track **pengukur tiga kali** lipat telah dibuat dalam beberapa situasi.

## Latar Belakang

Pengukur rel adalah spesifikasi paling mendasar dari sebuah kereta api. "**Trek rel**" dan "**set roda**" dibuat dalam "**toleransi teknik**" yang memungkinkan pergerakan lateral yang optimal dari set roda di antara rel. Pasangan rel yang menjadi terlalu lebar atau menyempit pada sepur akan menyebabkan derailment, terutama jika pelebaran sepur pada belokan melebihi batas normal.

Mengingat persyaratan untuk pengukur berada dalam batas yang sangat ketat, ketika jarak yang dirancang antara sepasang roda pada rangkaian roda sedikit berbeda dari yang lain di rel kereta api, jalur harus dibangun untuk dua pengukur khusus. Itu dicapai dengan berbagai cara: paling sering dengan menambahkan rel ketiga, lebih jarang dengan menambahkan sepasang rel lainnya; dan lebih jarang lagi, ketika ada tiga pengukur, dengan empat rel.

## Konfigurasi

Track pengukur ganda dapat terdiri dari tiga rel, berbagi satu rel "umum"; atau empat rel, dengan rel pengukur yang lebih sempit terletak di antara rel pengukur yang lebih luas. Pada konfigurasi tiga rel, keausan common rail lebih besar dibandingkan dengan dua rel luar lainnya. Di jalur pengukur ganda, turnout (Wesel) lebih kompleks daripada di jalur pengukur tunggal, dan kereta api harus diberi sinyal dengan aman di kedua pengukur. **"Sirkuit trek"** dan penguncian mekanis juga harus beroperasi pada kedua pengukur.

Lintasan *multi-gauge* sangat sering dikaitkan dengan stasiun *break-of-gauge*, di mana kendaraan rel atau muatan kendaraan dipindahkan dari satu pengukur ke pengukur lainnya. Kerusakan pada pengukur menyebabkan penundaan dan meningkatkan kemacetan, terutama pada jalur jalur tunggal. Pada dasarnya, dua kereta diperlukan untuk melakukan apa yang biasanya dilakukan oleh satu kereta. Ketika lalu lintas melewati terutama dalam satu arah, gerbong penuh yang dibawa ke perbatasan harus dikembalikan sebagai kosong, dan rangkaian gerbong kosong harus dibawa ke celah pengukur dari sisi lain untuk mengambil kargo. Kemacetan juga disebabkan oleh bongkar muat dan memuat ulang. Masalah ini diperparah ketika terjadi disparitas antara kapasitas lokomotif dan kendaraan di kedua gerbong: biasanya, satu muatan kereta api berukuran besar membutuhkan tiga kereta api berukuran sempit untuk mengangkutnya.

## Pengukur ganda (tiga rel)

Pembuatan track ukuran ganda dengan tiga rel dimungkinkan ketika dua rel yang berdekatan dapat dipisahkan di dasarnya dengan setidaknya ruang yang dibutuhkan oleh perangkat keras pengencang rel seperti paku dan atau klip rel – biasanya 40 milimeter (1,6 inci). Jika kedua pengukur lebih dekat dari itu, empat rel harus digunakan. Bergantung pada pengencang rel yang digunakan dan berat rel (rel berat lebih besar), perbedaan praktis antara kedua pengukur berada dalam kisaran 145 milimeter (5,7 inci) hingga 200 milimeter (7,9 inci).

## Pengukur ganda (empat rel)

Ada banyak tempat di mana dimensi pengukur dari dua sistem perkeretaapian yang berbeda terlalu dekat untuk memungkinkan konfigurasi tiga rel, termasuk:
*  dan  (umum di Afrika, masing-masing merupakan warisan dari praktik perkeretaapian Prancis/Belgia dan Inggris)
*  dan  (umum di Amerika Selatan)
*  dan  (umum di mana rel kereta api ukuran lebar bekas negara satelit Uni Soviet bertemu dengan pengukur standar Eropa atau Cina).
Dalam kasus seperti itu, diperlukan empat rel untuk pengukur ganda. Selain itu, empat rel dapat dihasilkan dari preferensi teknik ketika tiga rel sudah cukup: contohnya ada di "**Chemin de Fer de la Baie de Somme**" (kereta api Teluk Somme), yang menggabungkan pengukur standar dan meteran – 435 milimeter (17, 1 inci) berbeda, baik dalam parameter untuk tiga rel.

Empat rel juga dapat dikerahkan di mana garis tengah semua kendaraan rel harus disejajarkan dengan garis tengah lintasan. Contohnya adalah:

* dalam terowongan sempit
* peron penumpang, dimana demi alasan keamanan dan kenyamanan langkah yang diambil penumpang harus dalam batas yang seragam
* pada meja putar, yang harus menampilkan posisi rel yang identik di kedua ujungnya, yang mengharuskan keempat rel disejajarkan dengan poros tengah.

## Pengukur tiga

Dalam situasi yang jarang terjadi, tiga alat pengukur yang berbeda dapat menyatu ke halaman rel dan jalur pengukur tiga diperlukan untuk memenuhi kebutuhan operasional stasiun pengukur jarak – paling sering di mana tidak ada cukup ruang untuk melakukan sebaliknya. Akan tetapi, konstruksi dan pengoperasian jalur triple-gauge dan persinyalannya melibatkan biaya dan gangguan yang sangat besar, dan dilakukan ketika tidak ada alternatif lain yang tersedia.

Tabel berikut menunjukkan tempat-tempat di mana triple gauge diperlukan.

## Lebih dari tiga alat pengukur

Tiga alat pengukur adalah jumlah maksimum yang ditemukan di jalur kereta api yang beroperasi dan di pekarangan kereta api, tetapi beberapa produsen kereta api menempatkan lebih dari tiga jalur dalam pekerjaan mereka, tergantung pada alat pengukur khusus pelanggan mereka.

## Alternatif untuk trek pengukur ganda

Perpindahan barang dan penumpang antara alat pengukur yang berbeda tidak harus melibatkan jalur pengukur ganda: mungkin hanya ada dua jalur yang mendekati kedua sisi platform tanpa tumpang tindih. Di Australia, 13 stasiun break-of-gauge ada pada tahun 1945 sebagai hasil dari persaingan antarnegara bagian yang sudah berlangsung lama: tiga stasiun pengukur yang berbeda telah bertahan sejak tahun 1850-an dan lima ibu kota negara bagian tidak dihubungkan oleh pengukur standar hingga tahun 1995. 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. 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.

To cost and inefficiency was added, in the case of passengers, considerable inconvenience. 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".

In some locations, an alternative to building long lengths of dual-gauge track has been to change the wheels on rolling stock, either by dropping and changing wheelsets from 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 brake rigging and bogie centre pins have to be disconnected before the vehicle is lifted and new bogies are wheeled underneath.

In Europe, a similar principle embodies low-profile, small-wheeled transporter wagons, 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. The entire train is converted in minutes at a slow walking pace, each rollbock being automatically matched to its wheelset from underneath.

A further variant is "train on train", in which an entire narrow-gauge train is carried on standard-gauge flatcars on which continuous rail has been fitted.

Differences in gauge are also accommodated by gauge-adjustable wheelsets, which  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 predominates, and high-speed lines are laid to  standard gauge, there are many lines with narrower gauges ( and others).

## Dual-gauge railways by nation

;Australia
 In Victoria, there are sections of  and  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. Until 2008, there was a dual-gauge line between Wodonga and Bandiana.

At Albury railway station, New South Wales, a  and  dual-gauge line was in place until 2011. A dual-gauge line was within Tocumwal railway station until 1988, when the standard gauge component was put out of use.

In 1900, in South Australia, a three-rail dual-gauge system was proposed in order to avoid a break of gauge. However, designing turnouts was considered to be difficult due to the difference of only  between the  and the  broad gauge. After twenty years of discord, the proposal was abandoned. Much later, the South Australian Railways successfully adopted dual-gauge turnouts.

In Western Australia,  and  of double-track dual-gauge extends for  of the main line from East Perth to Northam. 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. The signalling system detects the gauge of the approaching train and puts the signals to stop if the route is set for the wrong gauge.

In Queensland, there is a section of  and  dual-gauge track between the rail freight yards at Acacia Ridge and Park Road station, which is utilised by both passenger and freight trains. Freight trains to the Port of Brisbane utilise the dual gauge Fisherman Islands line that runs parallel to the Cleveland railway line from Park Road to Lindum. 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 2012, a dual-gauge line was installed between Acacia Ridge and Bromelton to serve a new freight hub at Bromelton.

The  long Inland Railway, under construction in 2022, will have about  of dual gauge.

;Bangladesh
 The Bangladesh Railway uses three rails to avoid breaks of gauge between its broad-gauge and metre-gauge lines. The Jamuna Bridge and Padma Bridge, which link the east–west and north–south rail systems respectively, have four-rail dual-gauge tracks. Of the  Bangladseh Railway system, about  has four-rail dual-gauge.

;Belgium
 Tram tracks in Brussels once combined  lines for inter-urban trams and  lines for urban trams in a three-rail layout. In 1991, the interurban trams went out of service and then the network used only standard-gauge track.

;Bulgaria
 The Sofia tramway uses a mixture of narrow and standard gauge. A  section of track between Krasna polyana depot and Pirotska street is dual-gauge shared by  route 22 and  route 11.

;Cameroon
 The new port of Kribi may serve 1000mm gauge bauxite traffic as well as 1435mm gauge iron ore traffic.

;Czech Republic
 In the Czech Republic, there is 2&nbsp;km of dual gauge  and  track near Jindřichův Hradec. In 1985, its original four rails were converted to three rails. 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 standard gauge train had been switched on to the narrow gauge track.

;France
 The Chemin de Fer de la Baie de Somme in France is dual gauge between Noyelles-sur-Mer and Saint-Valery-sur-Somme. The line has four rails with metre gauge laid within standard gauge. There are some dual-gauge (standard and Iberian) sidings at Cerbère on the Spanish border.

;Germany
 In the 1970s, the Stuttgarter Straßenbahnen tram lines underwent a gauge conversion from  gauge to standard gauge. This was part of an upgrade to the Stuttgart Stadtbahn. In 1981,  and  dual-gauge track was constructed so that new DT-8 Stadtbahn cars and old trams could share the network. In 2008, a further gauge conversion was completed. The Stuttgart Straßenbahn Museum operates  gauge trams on weekends and special occasions.

In Krefeld on Ostwall, Germany, tram lines are dual gauge so that standard  Rheinbahn U76 Stadtbahn cars and  gauge trams may share the lines. At the north end of the route, at the junction with Rheinstraße, the trams reverse. There, the standard gauge line ends, while the metre gauge lines continue. At the Hauptbahnhof, on Oppumer Straße, dual gauge track continues. At the ends of Oppumer Straße, the two tracks diverge.

In Mülheim there is a similar situation. The Duisburg tram line 901 meets the local line 102. The tram system in Duisburg uses  gauge track while the tram route from Witten to Mülheim uses  gauge tracks. Two lines share a tunnel section between the Mülheim (Ruhr) Hauptbahnhof and Schloss Broich then diverge at street level.

The tram network between Werne to Bad Honnef is large with various operators and gauges. The trams in Wuppertal used  gauge track on eastwest lines and  gauge track on northsouth lines. Trams in Duisburg used  gauge track on lines south of the Ruhr and  gauge tracks on lines north of the Ruhr. The north lines closed in the 1960s and 1970s. Duisburg's three routes were converted to  gauge track.

;Ghana
 Ghana is converting its narrow gauge to standard gauge, and is installing dual-gauge sleepers as an intermediate stage.

;Greece
 In Greece, the line between Athens and Elefsis (now closed) was dual gauge in order to allow the  gauge trains of the Peloponnese rail network to pass. It also allowed standard gauge trains to reach the Elefsis shipyards. In Volos, a short section of track between the main station and the harbour used an unusual triple gauge, to accommodate standard gauge trains from Larissa, metre gauge trains from Kalambaka, and the  gauge trains of the Pelion railway.

;Indonesia
 In 1899, in the Dutch East Indies, dual gauge track was installed between Yogyakarta and Solo. The track was owned by the Nederlandsch-Indische Spoorweg Maatschappij, a private company, which in 1867 had built the  gauge line. The third rail was installed to allow passengers and goods travelling over the  gauge *Staatsspoorweg* (state railway) a direct connection. At a later date, the government constructed new tracks to allow greater capacity and higher speeds. In 1940, a third rail was installed between Solo and Gundih on the line to Semarang, allowing  gauge trains to travel between Semarang, Solo and Yogyakarta via Gambringan, on the line to Surabaya instead of on the original line via Kedungjati.

In 1942 and 1943 in Java, under Japanese military occupation, conversion from took place  to  on the BrumbungKedungjatiGundih main line and the KedungjatiAmbarawa branch line.

Until the 1970s, a short section of dual gauge  and  line existed in North Sumatra on a joint line of the Deli Railway and the Atjeh Tram.

Some sugar mill railways in Java have dual-gauge sections.

;Ireland
 Ireland's Ulster Railway underwent a gauge conversion from 1880mm to the new Irish standard of . The Dublin & Drogheda Railway underwent a gauge conversion because the gauges were too close to allow a dual-gauge line.

;Italy
 The Potenza  Avigliano Lucania line in Italy is a dual gauge rail with  and  tracks.

;Japan
 In Japan, the national standard is  narrow gauge. Dual gauge is used where the  Shinkansen (bullet train) lines join the main network. For example, part of the Ōu Main Line became part of the Akita Shinkansen and was converted to dual gauge in a limited section. The longest () dual gauge section in Japan is near, and in, the Seikan Tunnel. Sections of the Hakone Tozan Line are among a number of other dual-gauge lines.

;Mexico
 Mexico previously had  and  dual gauge track.

;Netherlands
 The first railway lines in the Netherlands were constructed with a track gauge of . For the 1939 centennial celebration, an exact replica of the country's first locomotive "De Arend" was built using the original blueprints. Since 1953, the locomotive is housed at the Dutch National Railway Museum, where in recent years, a dual-gauge track has been constructed in the rail yard, allowing for the locomotive to drive back and forth on special occasions.

;Poland
 In Poland, there is  of  and  dual-gauge track in the Greater Poland Voivodeship, linking Pleszew with a nearby mainline station. It is served by narrow-gauge passenger trains and standard-gauge freight trains.

;Russia
 Between 2008 and 2012, a  dual-gauge cross-border track was rebuilt between Khasan, Russia, and Rajin, North Korea; its gauges were the Russian  and Korean .

;Spain
 In Spain, there is  of dual gauge in the AVE line from Zaragoza to Huesca, usable for both  standard-gauge high-speed trains and  Spanish network trains. Some dual-gauge sidings are at Port Bou on the French border. In 2009, Adif called for tenders for the installation of a third rail for standard-gauge trains on the  between Castellbisbal and the Can Tunis freight terminal in Barcelona.

;Sweden
 The bridges at the borders of Sweden and Finland, between Haparanda and Tornio have  of dual gauge,  and  track. At each end of the dual-gauge section are yards with standard and Finnish gauge areas to allow for trans-shipment. Four rails are used because the gauges are close and the bridge structure is wider than normal to allow for the offset from the centreline of each gauge. A Rafil gauge changer is at the Tornio yard. Similar arrangements exist on the approach to Kaliningrad, where  track extends from the Polish border with some sections of dual gauge.

Between Västervik and Jenny, Sweden, there is a  and  dual-gauge line and dual-gauge track in the Västervik station area.

;Switzerland
 In Switzerland, dual-gauge  track and  track exists between Lucerne and Horw of the Zentralbahn, between Niederbipp and Oberbipp of the Oberaargau-Jura Railways and between Chur and Domat/Ems of RhB. All three allow narrow-gauge passenger trains and standard-gauge freight trains to operate. A ″non-stop″ scheme (albeit with a pause to change locomotives) on the Montreux-Interlaken route was inaugurated in December 2022. The former Zollikofen-Worblaufen-Deisswil dual gauge was cut back to Papiermühle when the factory in Deisswil closed.

;United Kingdom
 The Great Western Railway in Britain was originally built to a broad gauge of 2134&nbsp;mm (7&nbsp;ft 0 in), subsequently widened to 2140&nbsp;mm (7&nbsp;ft 0 in). After a "gauge war", the gauge was converted to . A dual-gauge system was easily installed as the gauges were well separated and the line had wooden sleepers. 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. Two of the city's stations were on a narrow  gauge. The other two city stations were on broad  gauge.

;United States
 In Los Angeles, the  Los Angeles Railway and  Pacific Electric Railway ran on dual gauge track on some downtown streets.

From 1880 to 1902, the Burlington, Cedar Rapids and Northern Railway (standard gauge) and the Burlington and Northwestern Railway (narrow gauge) shared a dual-gauge mainline from Burlington, Iowa to Mediapolis,  to the north.

The early operational years of the State Belt Railroad in San Francisco featured dual-gauge tracks to accommodate regional railroads of the time, which interchanged via ferry.

Until 1941, the Colorado and Southern Railway used both standard-gauge and narrow-gauge tracks, and had a dual-gauge line between Denver and Golden, Colorado.

Until the 1960s, the Denver and Rio Grande Western Railroad's Alamosa–Durango Line from Alamosa, Colorado to Antonito was dual-gauge.

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

Apart from the Los Angeles Railway and the Pacific Electric Railway, the examples were  and .

;Vietnam
 In Vietnam, near the border with China, there is  and  dual-gauge track between Hanoi and Đồng Đăng. Other smaller dual-gauge sections exist elsewhere in the north-east of the country.

## Lihat pula

* Broad-gauge railway
* Gauntlet track
* Glossary of rail transport terms
* History of rail transport
* Rail transport
* Rail transport by country
* Tamping machines
* Track gauge conversion

## Notes

 
## Notes to gallery photos

## Referensi

## Further reading
* 
* 

## Pranala luar
* Jane's World Railways (hard copy)
* Jindřichův Hradec Local Railways
* Jindřichohradecké úzké mainly in Czech
* South Australia – Rail Revitalisation Project  `registration`: a free registration is required to access the source.
* Columbus' streetcar track gauge
*