Horseshoe curve

Last updated
Switchback in Utah.jpg
A road switchbacks into a canyon in Utah's Canyonlands National Park.
Horseshoe Curve aerial photo, March 2006.jpg
Aerial shot of the Horseshoe Curve that helps trains cross the Allegheny Mountains west of Altoona, Pennsylvania.

A horseshoe curve is a class of climbing curve in a roadbed that reverses turn direction (inflection) twice on either side of a single tight curve that varies through an angle of about 180 degrees or more.

Contents

Such curves are more commonly found in a railway line but are also used in roads. The characteristic U shape, or even slight balloon shape, of such a curve resembles a horseshoe. On roadways, particularly tight versions of such curves are typically called hairpin turns.

Theory

A horseshoe curve is a means to lengthen an ascending or descending grade and thereby reduce the maximum gradient. Grade or gradient is defined as the rise divided by the run (length) or distance, so in principle such curves add to length for the same altitude gain, just as would a climbing spiral around one or more peaks, or a climbing traverse (cutting) wrapping around an end of a ridge.

If the straight route between two points is too steep to climb, a more circuitous route will increase the distance traveled, allowing the difference in altitude to be averaged over a longer track (or road) length. Unlike a spiral, a horseshoe curve does not involve the track crossing over itself, and the full horseshoe involves both relatively straight sections, curve deflections in both directions and tightly curved segment; while a spiral generally has a more uniform curvature. Obviously, a horseshoe also gives rise to a severe change in direction requiring another corrective curve to regain displacement in the overall direction of travel, while a spiral generally does not.

A horseshoe curve is sometimes used where the route bridges a deep gully. Deviating from a straight-line route along the edge of the gully may allow it to be crossed at a better location.

Horseshoe curves are common on railway lines in steeply graded or hilly country, where means must be found to achieve acceptable grades and minimize construction costs. As with spirals, the main limitation in laying out a horseshoe is keeping its radius as large as possible, as sharp curves limit train speed, and through increased friction, are harder on rails, requiring more frequent replacement of outer tracks.

Examples

Europe

Germany

Norway

Map of Storegjeltunnelen and Dalbergtunnelen in Mabodalen gorge, a complex system of horseshoe curves, tunnels and loops on Norwegian National Road 7. Storegjeltunnelen OSM.JPG
Map of Storegjeltunnelen and Dalbergtunnelen in Måbødalen gorge, a complex system of horseshoe curves, tunnels and loops on Norwegian National Road 7.
The Flam Line, 1926 shortly after construction
Credit: Anders Beer Wilse Vatnahalsen-Reinunga Wilse 1939.jpg
The Flåm Line, 1926 shortly after construction
Credit: Anders Beer Wilse
  • The Dovre Line, the main line of the Norwegian railway network, has a horseshoe within Grønbogen tunnel from Dombås at the steep hills to the Dovre plateau, standard gauge, single track. [1]
  • The Flåm Line, Norway, has a double horseshoe, one inside a tunnel, one in the open, few kilometres below top station, standard gauge, single track.
  • The Rauma Line, Norway, has a double horseshoe through the steep and narrow valley at Verma, one inside a tunnel and one that includes the Kylling Bridge, standard gauge, single track.

Poland

Slovakia

United Kingdom

  • Newcastle Quayside branch, a goods-only railway from the main line to the river quayside, through a steeply descending horseshoe tunnel.
  • The horseshoe curve on the West Highland Line in Scotland between Upper Tyndrum and Bridge of Orchy was built because the engineers of the railway couldn't afford to build a viaduct crossing the remote valley.

North America

United States

Pennsylvania

Alaska

  • In the Loop District of the Alaska Railroad between mileposts 48 and 51 northeast of Seward, Alaska, there was a horseshoe and a spiral, both on an extensive range of timber trestles up to 106 feet high. In 1951, a new route removed the original horseshoe, the spiral and all the trestles but added a new horseshoe at milepost 48. [2]

California

Colorado

Horseshoe curves were used extensively on the many narrow gauge railroads in the Colorado Rocky Mountains, now mostly abandoned, [4] for example:

  • On the Cumbres and Toltec Scenic Railroad (formerly D&RGW); 3 ft (914 mm) gauge:
    • Coxo Curve; Cumbres, Colorado
    • Tanglefoot Curve; Cumbres, Colorado
    • Los Pinos Curve; Los Pinos, Colorado
    • Phantom Curve; Sublette, New Mexico
    • Whiplash Curve; Big Horn, Colorado
    • Lava Loop; Lava, Colorado
  • Ophir Loop; Ophir, Colorado; Rio Grande Southern Railroad  3 ft (914 mm) gauge (abandoned)
  • Altura Curve; Altura, Colorado; Rio Grande, Pagosa and Northern; 3 ft (914 mm) gauge (abandoned)
  • On the Uintah Railway; 3 ft (914 mm) gauge (abandoned): [5]
    • 66° curve; Moro Castle, Colorado;
    • Balloon Loop; Columbine, Colorado
    • Hairpin Curve and Muleshoe Curve; McAndrews, Colorado

Idaho

Maryland

Montana

Nevada

  • Arnold Loop; on the eastern approach to Silver Zone Pass in the Toano Range in eastern Nevada; Union Pacific (formerly Western Pacific).

New York

  • Swain, New York; Pittsburg, Shawmut, & Northern Railroad (abandoned)
  • Richburg, New York; Pittsburg, Shawmut, & Northern Railroad (abandoned)

Oregon

Utah

Washington

Canada

British Columbia

  • Notch Hill, on CP's Shuswap Sub near Salmon Arm, British Columbia.

Asia

China

Jiangsu

Shaanxi

Sichuan

Xinjiang

Yunnan

Gansu

Qinghai

  • Guanjiao Curve Group, Qinghai–Tibet Railway
    • Erlang Curve.
    • Erlang North Curve.
    • Nanshan Curve.
    • Luobei Curve.
    • Luobei South Curve.

Iran

Japan

Oceania

Australia

New Zealand

Related Research Articles

<span class="mw-page-title-main">Denver and Rio Grande Western Railroad</span> American railroad company

The Denver and Rio Grande Western Railroad, often shortened to Rio Grande, D&RG or D&RGW, formerly the Denver & Rio Grande Railroad, was an American Class I railroad company. The railroad started as a 3 ft narrow-gauge line running south from Denver, Colorado, in 1870. It served mainly as a transcontinental bridge line between Denver and Salt Lake City, Utah. The Rio Grande was also a major origin of coal and mineral traffic.

<span class="mw-page-title-main">Mountain railway</span> Railway which operates within a mountainous region

A mountain railway is a railway that operates in a mountainous region. It may operate through the mountains by following mountain valleys and tunneling beneath mountain passes, or it may climb a mountain to provide transport to and from the summit.

<span class="mw-page-title-main">Zig zag (railway)</span> Type of railway line used to climb steep gradients

A railway zig zag or switchback is a railway operation in which a train is required to switch its direction of travel in order to continue its journey. While this may be required purely from an operations standpoint, it is also ideal for climbing steep gradients with minimal need for tunnels and heavy earthworks. For a short distance, the direction of travel is reversed, before the original direction is resumed. Some switchbacks do not come in pairs, and the train may then need to travel backwards for a considerable distance.

<span class="mw-page-title-main">Spiral (railway)</span> Railway layout for steep climbs

A spiral is a technique employed by railways to ascend steep hills.

<span class="mw-page-title-main">Cincinnati, Lebanon and Northern Railway</span> Ohio railroad (1885–1926)

The Cincinnati, Lebanon and Northern Railway (CL&N) was a local passenger and freight-carrying railroad in the southwestern part of the U.S. state of Ohio, connecting Cincinnati to Dayton via Lebanon. It was built in the late 19th century to give the town of Lebanon and Warren County better transportation facilities. The railroad was locally known as the "Highland Route", since it followed the ridge between the Little and Great Miami rivers, and was the only line not affected by floods such as the Great Dayton Flood of 1913.

<span class="mw-page-title-main">Denver, South Park and Pacific Railroad</span> Historic railroad in Colorado, U.S.

The Denver, South Park, and Pacific Railroad was a historic 3 ft narrow gauge railroad that operated in Colorado in the western United States in the late 19th century. The railroad opened up the first rail routes to a large section of the central Colorado mining district in the decades of the mineral boom. The railroad took its name from the fact that its main line from Denver ascended the Platte Canyon and traversed South Park, hence its popular name "The South Park Line." Despite its lofty goals, the line never connected itself with the Pacific or any transcontinental line, apart from its terminal at Denver Union Station.

<span class="mw-page-title-main">Double-track railway</span> Route where trains traveling in each direction can quickly pass each other

A double-track railway usually involves running one track in each direction, compared to a single-track railway where trains in both directions share the same track.

<span class="mw-page-title-main">Georgetown Loop Railroad</span>

The Georgetown Loop Railroad is a 3 ft narrow gauge United States heritage railroad located in the Rocky Mountains in Clear Creek County, adjacent to Interstate 70 in Colorado.

<span class="mw-page-title-main">Pittsburg, Shawmut and Northern Railroad</span>

The Pittsburg, Shawmut & Northern Railroad also known as the Shawmut Line, was a Class I railroad company operating passenger and freight service on standard gauge track in central Pennsylvania and western New York. The line was financially troubled for its entire life span and declared bankruptcy after just six years of operation. It would spend the remaining 42 year of its existence in receivership or trusteeship: one of the longest bankruptcy proceedings in American railroading history.

<span class="mw-page-title-main">Cumbres and Toltec Scenic Railroad</span> Heritage railroad in Colorado and New Mexico, U.S.

The Cumbres and Toltec Scenic Railroad, often abbreviated as the C&TSRR, is a 3 ft narrow-gauge heritage railroad that operates on 64 miles (103 km) of track between Antonito, Colorado, and Chama, New Mexico, in the United States. The railroad is named for two geographical features along the route: the 10,015-foot (3,053 m)-high Cumbres Pass and the Toltec Gorge. Originally part of the Denver and Rio Grande Western Railroad's narrow-gauge network, the line has been jointly owned by the states of Colorado and New Mexico since 1970. Today, the C&TSRR is one of only two remaining parts of the former D&RGW narrow-gauge network, the other being the Durango and Silverton Narrow Gauge Railroad (D&SNG), which runs between the communities of Durango and Silverton, Colorado. The railroad has a total of ten narrow-gauge steam locomotives and two narrow-gauge diesel locomotives on its current roster. The railroad also operates two smaller former D&RGW steam locomotives, Nos. 315 and 168, for special events and excursions.

<span class="mw-page-title-main">Roaring Camp & Big Trees Narrow Gauge Railroad</span>

The Roaring Camp & Big Trees Narrow Gauge Railroad is a 3 ft narrow-gauge tourist railroad in California that starts from the Roaring Camp depot in Felton, California and runs up steep grades through redwood forests to the top of nearby Bear Mountain, a distance of 3.25 miles.

<span class="mw-page-title-main">South Pacific Coast Railroad</span>

The South Pacific Coast Railroad (SPC) was a 3 ft narrow gauge steam railroad running between Santa Cruz, California and Alameda, with a ferry connection in Alameda to San Francisco. The railroad was created as the Santa Clara Valley Railroad, founded by local strawberry growers as a way to get their crops to market in San Francisco and provide an alternative to the Southern Pacific Railroad. In 1876, James Graham Fair, a Comstock Lode silver baron, bought the line and extended it into the Santa Cruz Mountains to capture the significant lumber traffic coming out of the redwood forests. The narrow-gauge line was originally laid with 52-pound-per-yard (26 kg/m) rail on 8-foot (2.44 m) redwood ties; and was later acquired by the Southern Pacific and converted to 4 ft 8+12 instandard gauge.

<span class="mw-page-title-main">Colorado and Southern Railway</span> American Class I railroad

The Colorado and Southern Railway was an American Class I railroad in the western United States that operated independently from 1898 to 1908, then as part of the Chicago, Burlington and Quincy Railroad until it was absorbed into the Burlington Northern Railroad in 1981.

<span class="mw-page-title-main">Narrow-gauge railroads in the United States</span>

Standard gauge was favored for railway construction in the United States, although a fairly large narrow-gauge system developed in the Rocky Mountains of Colorado and Utah. Isolated narrow-gauge lines were built in many areas to minimize construction costs for industrial transport or resort access, and some of these lines offered common carrier service. Outside Colorado, these isolated lines evolved into regional narrow-gauge systems in Maine, New York, Pennsylvania, Ohio, Iowa, Hawaii, and Alaska.

<span class="mw-page-title-main">Utah Division (D&RGW)</span> Rail line in Utah and Colorado

The Utah Division of the former Denver & Rio Grande Western Railroad (D&RGW) is a rail line that connects Grand Junction, Colorado and Salt Lake City, Utah in the Western United States. It is now incorporated into the Union Pacific Railroad (UP) system as part of the Central Corridor. The modern Union Pacific has split the line into two subdivisions for operational purposes, the Green River Subdivision between Grand Junction and Helper, Utah and the Provo Subdivision from Helper to Salt Lake City. Daily passenger service is provided by Amtrak's California Zephyr; the BNSF Railway and Utah Railway have trackage rights over the line.

<span class="mw-page-title-main">Kunming–Haiphong railway</span> Railway in Vietnam and China

The Yunnan–Haiphong railway is an 855 km (531 mi) railway built by France from 1904 to 1910, connecting Haiphong, Vietnam, with Kunming, Yunnan province, China. The section within China from Kunming to Hekou is known as the Kunming–Hekou railway, and is 466 km (290 mi) long. The section within Vietnam is 389 km (242 mi) long, and is known as the Hanoi–Lào Cai railway. The railway was built with 1,000 mm gauge due to the mountainous terrain along the route. Currently it is the only main line in China using 1,000 mmmetre gauge.

<span class="mw-page-title-main">Central Corridor (Union Pacific Railroad)</span>

The Central Corridor is a rail line operated by the Union Pacific Railroad from near Winnemucca, Nevada to Denver, Colorado in the western United States. The line was created after the merger with the Southern Pacific Transportation Company by combining portions of lines built by former competitors. No portion of the line was originally built by the Union Pacific; in fact, some portions were built specifically to compete with the Union Pacific's Overland Route. The line is known for significant feats of engineering while crossing the Wasatch Mountains of Utah and the Rocky Mountains of Colorado. The line features numerous tunnels, the longest and highest of these is the Moffat Tunnel.

<span class="mw-page-title-main">Chengdu–Kunming railway</span> Railway line in China

The Chengdu–Kunming railway or Chengkun railway, is a major trunkline railroad in southwestern China between Chengdu, the capital of Sichuan Province and Kunming, the capital of Yunnan Province. The line is 1,134 km (705 mi) long and traverses rugged terrain from the Sichuan Basin to the Yunnan-Guizhou Plateau. The line was built between 1958 and 1970, with much of the work coming during the Third Front campaign to develop industry in China's interior. Major cities along route include Chengdu, Pengshan, Jiajiang, Emei, Ebian, Ganluo, Xide, Xichang, Dechang, Miyi and Panzhihua in Sichuan Province and Yuanmou, Lufeng, Anning and Kunming in Yunnan Province.

<span class="mw-page-title-main">Alamosa–Durango line</span> Historic railroad line

The Alamosa–Durango line or San Juan extension was a railroad line built by the Denver and Rio Grande Western Railroad, following the border between the U.S. states of Colorado and New Mexico, in the Rocky Mountains. The line was originally built as a 3 ft narrow-gauge line between Alamosa, Colorado, and Durango, Colorado. Portions of the route survive to this day: the now standard-gauged segment from Alamosa to Antonito, Colorado, and a narrow-gauge portion from Antonito to Chama, New Mexico.

References

  1. Avslutningsrapport for Dovrebanen: avgit til Den kgl. norske regjerings departement for de offentlige arbeider. Oslo: Baneforlaget. 1926 (original), 2000 (reprint). ISBN   82-91448-35-3.
  2. Prince, B.D. The Alaska Railroad in Pictures 1914-1964, Ken Wray's Print Shop, Anchorage, 1964
  3. Crump, Spencer (1998). Redwoods, Iron Horses, and the Pacific (Fifth ed.). Fort Bragg, California: California Western Railroad. p. 60. ISBN   0-918376-12-2.
  4. Ormes, R.M. Tracking Ghost Railroads in Colorado, Century One Press 1975 (Contains extensive local maps identifying railroad names and dates of service).
  5. Bender, Henry E Jr. (1970). Uintah Railway: The Gilsonite Route. Berkeley, California: Howell-North Books. p. 42. ISBN   0-8310-7080-3.
  6. "404,您访问的页面已经不存在!". www.sohu.com. Retrieved 2021-07-21.{{cite web}}: Cite uses generic title (help)
  7. John Brian Hollingsworth (1982). Atlas of the world's railways. Bison.
  8. Hugh Hughes (1981). Middle East railways. Continental Railway Circle.