5 ft 6 in gauge railway
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|Tram · Rapid transit
Miniature · Scale model
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|Change of gauge|
|Break-of-gauge · Dual gauge ·
Conversion (list) · Bogie exchange · Variable gauge
5 ft 6 in/1,676 mm is the size of a broad track gauge commonly used in India, Pakistan, west of Bangladesh, Sri Lanka, Argentina, Chile, and on the BART (Bay Area Rapid Transit) in the San Francisco Bay Area. In South Asia it is simply known as "Broad gauge", while in North America, it is called Provincial, Portland, or Texas gauge. Elsewhere it is known as "Indian gauge". It is the widest gauge in regular passenger use anywhere in the world.
In British India, some standard gauge freight railways were built in initial period, though they were dismantled later. Later, in 1850s, the gauge of 1,676 mm (5 ft 6 in) was adopted as standard for the nation-wide network.
Rail transport in India today is predominantly on 1,676 mm (5 ft 6 in) broad gauge barring heritage railways. Small stretches of the network use metre and narrow gauges. Urban rail is mostly on standard gauge, although some initial lines use 1,676 mm (5 ft 6 in) broad gauge.
Bangladesh Railways uses a mix of 1,676 mm (5 ft 6 in) broad gauge and metre gauge. The broad gauge network is primarily located to the west of the Jamuna River, while the metre gauge network is primarily located to its east. The Jamuna Bridge is a mixed use bridge that contains a dual gauge connection across the river linking both networks.
In Nepal all services currently operate on 1,676 mm (5 ft 6 in) broad gauge only.
In Pakistan, all services currently operate on 1,676 mm (5 ft 6 in) broad gauge only.
In Sri Lanka, all services currently operate on 1,676 mm (5 ft 6 in) broad gauge only.
The 1,676 mm (5 ft 6 in) broad gauge was actually first used in Scotland for two short, isolated lines, the Dundee and Arbroath Railway (1836-1847) and the Arbroath and Forfar Railway (1838- ). Both the lines were subsequently converted to standard gauge.
Canada became the first British colony, in the 1850s, to use 1,676 mm (5 ft 6 in) broad gauge. It was known as the "Provincial gauge" in Canada.
The Grand Trunk Railway which operated in several Canadian provinces (Quebec and Ontario) and American states (Connecticut, Maine, Massachusetts, New Hampshire, and Vermont) used it, but was changed to standard gauge in 1873. The Grand Trunk Railway which operated from headquarters in Montreal, Quebec, although corporate headquarters were in London, England. The St. Lawrence and Atlantic Railroad which operated in Quebec, Vermont, New Hampshire and Maine also used it but was converted in 1873.
There is a longstanding rumour that the Provincial gauge was selected specifically to create a break-of-gauge with US railways, the War of 1812 still being a fresh memory. However, there is little supporting evidence for this, and this story appears to be traced to a single claim from the late 1800s.
The Bay Area Rapid Transit system is the only operating railroad in the United States to use 1,676 mm (5 ft 6 in) broad gauge, with 109 miles (175 km) of double tracked routes. The original engineers for the system had background in aerospace (rather than railroads) and intended to make a state-of-the-art system for other municipalities to emulate. The use of 1,676 mm (5 ft 6 in) broad gauge rails was one of many unconventional design elements included in its design which, in addition to its unusual gauge, also uses flat-edge rail, rather than typical rail that angles slightly inward. This has complicated maintenance of the system, as it requires custom wheelsets, brake systems, and track maintenance vehicles.
The New Orleans, Opelousas and Great Western Railroad (NOO&GW) used 1,676 mm (5 ft 6 in) broad gauge until 1872, and the Texas and New Orleans Railroad used 1,676 mm (5 ft 6 in) broad gauge, ("Texas gauge") until 1876. The Grand Trunk Railway predecessor St. Lawrence and Atlantic Railroad which operated in Quebec, Vermont, New Hampshire and Maine also used 1,676 mm (5 ft 6 in) broad gauge ("Canadian gauge" or "Portland gauge") but was converted in 1873. Several Maine railroads connected to the Grand Trunk Railway shared its "Portland Gauge". The Androscoggin and Kennebec Railroad and the Buckfield Branch Railroad were later consolidated as the Maine Central Railroad which converted to standard gauge in 1871. The only electric streetcar system in the U.S. to use this gauge was that of Fairfield, Maine.
- Frost heaves (swelling of wet soil upon freezing) produce an uneven running surface causing an irregular rocking motion as trains moved past. A wider wheelbase offered a steadier ride with less wear on the machinery and roadbed.
- Wider cars offered more room for passengers and cargo. Train length would be reduced for cars carrying the same amount of cargo. Shorter trains would lessen the effects of side winds, and permit more efficient application of power.
- Wide gauge locomotives offered more room to place reciprocating machinery inside, rather than outside the driving wheels. Reciprocating machinery was a source of vibration before mechanical engineering encompassed a good understanding of dynamics; and keeping such vibration close to the center of mass reduced the angular momentum causing rocking.
- Wider fireboxes and boilers allowed more powerful locomotives. The alternative of longer boilers held the disadvantage of poor firebox draft through the increased frictional resistance of longer boiler tubes.
- More powerful locomotives carrying fewer, larger cars would have reduced manpower requirement for engine crews and shop personnel.
- For locomotives of equal power, fuel consumption increased as gauge decreased, especially in colder outside temperatures.
- More powerful wide gauge locomotives would be more capable for plowing snow; and thereby provide more reliable winter service.
- Several gauges were in widespread use, and none had yet come into clear dominance.
- Freight transfer was preferable to exchange of cars between railways because unowned cars were abused on foreign railways.
- The Grand Trunk Railway system feeding the seaport of Portland, Maine offered little need for gauge transfer prior to loading on export shipping.
- Potential advantages of freight transfer to the standard gauge railroad from Portland to Boston seemed insignificant as long as competitive rates were available for transport on steamships between the two ports.
- The majority of Canadian freight anticipated to be carried over rail lines to Portland was heavy and bulky in comparison to its value, and must be transported cheaply in large quantities to maintain profitability for producers and transporters.
The national railway network is predominantly on 1,676 mm (5 ft 6 in) broad gauge.
Most installations of 1,676 mm (5 ft 6 in) broad gauge railways are in the south of the country.
Similar gauges and compatibility
The Iberian gauge (1,668 mm or 5 ft 5 21⁄32 in) is closely similar, with only 8 mm (5⁄16 in) difference, and allows compatibility with the rolling stock. For example, in recent years Chile and Argentina have bought second hand Spanish/Portuguese Iberian-gauge rolling stock. 1668mm trains can run on 1676mm gauge without adaptation, but for better stability in high-speed running a little wheelset adjustment may be required (for example - Russian-Finnish train Allegro has gauge 1522 mm, intermediate between Russian 1520 mm and Finnish 1524 mm). Backward compatibility - 1676 mm trains on 1668 mm gauge is possible, but no examples and data exist. Due to the narrower gauge, a strong wear of wheelsets may occur without adjustment.
|Argentina||San Martín Railway||operating|
|Argentina||Mitre Railway||except Tren de la Costa in standard gauge; operating|
|Argentina||Roca Railway||except La Trochita, Central Chubut Railway and Ramal Ferro Industrial de Río Turbio in 750 mm (2 ft 5 1⁄2 in) gauge; operating|
|Bangladesh||Bangladesh Railway||682 km (424 mi)||operating|
|Canada||Grand Trunk Railway||converted to standard gauge in 1873|
|Canada||St. Lawrence and Atlantic Railroad||converted to standard gauge in 1873|
|Canada||Champlain and St. Lawrence Railroad||converted to standard gauge in 1873; specific names, Provincial gauge|
|Canada||Grand Trunk Railway of Canada||converted to standard gauge|
|Canada||Intercolonial Railway of Canada||converted to standard gauge in 1875|
|Chile||*Empresa de los Ferrocarriles del Estado||operating|
|India||Indian Railways||108,500 km (67,400 mi)||operating|
|India||Delhi Metro||65 km (40 mi)||Phase-1 lines only; operating|
|India||Kolkata Metro||27.22 km (16.91 mi)||Line 1; operating|
|Nepal||Nepal Railways||59 km (37 mi)||operating|
|Pakistan||Pakistan Railways||7,791 km (4,841 mi)||operating|
|Paraguay||Paraguayan railway||From Asunción to Encarnación was originally laid in this gauge in the hope that the connecting line from Posadas to Buenos Aires would be built to the same gauge; that line was laid to standard gauge, and when the FCPCAL reached Encarnación in 1912 the whole line had to be re-gauged to standard gauge to allow through-working.|
|Sri Lanka||Sri Lanka Railways||1,508 km (937 mi)||operating|
|United Kingdom||Arbroath and Forfar Railway||see Scotch gauge, converted to standard gauge|
|United Kingdom||Dundee and Arbroath Railway||16 3⁄4 mi (27.0 km)||see Scotch gauge, converted to standard gauge|
|United States||Bay Area Rapid Transit (BART) San Francisco Bay Area||109 mi (175 km)||operating|
|United States||Maine Central Railroad||converted to standard gauge in 1871|
- Omer Lavallee, "The Rise and Fall of the Provincial Gauge", Canadian Rail, February 1963, pp. 22-37
- Gafni, Matthias (March 25, 2016). "Has BART's cutting-edge 1972 technology design come back to haunt it?". San Jose Mercury News. Retrieved March 28, 2016.
- Holt, Jeff (1985). The Grand Trunk in New England. Railfare. p. 78. ISBN 0-919130-43-7.
- "Canada's Digital Collections archived at Library and Archives Canada". Government of Canada. Retrieved 2007-11-29.