An aerial tramway (U.S. English), cable car (British English), ropeway (Japanese) or aerial tram is a type of aerial lift which uses one or two stationary ropes for support while a third moving rope provides propulsion.[1] With this form of lift, the grip of an aerial tramway cabin is fixed onto the propulsion rope and cannot be decoupled from it during operations.
Contents |
Because of the proliferation of such systems in the Alpine regions of Europe, the French and German language names of téléphérique and Seilbahn, respectively, are often also used in an English language context. Cable car is the usual term in British English, as in British English the word tramway generally refers to a railed street tramway while in American English, cable car is most often associated with a type of cable-pulled street tramway with detachable vehicles; e.g., San Francisco's cable cars. As such, careful phrasing is necessary to prevent confusion. It is also sometimes called a ropeway or even incorrectly referred to as a gondola lift. A gondola lift has cabins suspended from a continuously circulating cable whereas aerial trams simply shuttle back and forth on cables. In Japan, the two are considered as a same vehicle and called ropeway, while the term cable car means Cable car (railway) and funicular.
An aerial tramway consists of one or two fixed cables (called track cables), one loop of cable (called a haulage rope), and two passenger cabins. The fixed cables provide support for the cabins while the haulage rope, by means of a grip, is solidly connected to the truck (the wheel set that rolls on the track cables). An electric motor drives the haulage rope which provides propulsion. Aerial tramways are constructed as reversible systems; vehicles shuttling back and forth between two end terminals and propelled by a cable loop which stops and reverses direction when the cabins arrive at the end stations. Aerial tramways differ from gondola lifts in that gondola lifts are considered continuous systems (cabins attached onto a circulating haul rope that moves continuously).[2]
Two-car tramways use a jig-back system: A large electric motor is located at the bottom of the tramway so that it effectively pulls one cabin down, using that cabin's weight to help pull the other cabin up. A similar system of cables is used in a funicular railway. The two passenger cabins, which carry from 4 to over 150 people, are situated at opposite ends of the loops of cable. Thus, while one is coming up, the other is going down the mountain, and they pass each other midway on the cable span.
Some aerial trams have only one cabin, which lends itself better for systems with small elevation changes along the cable run.
The first aerial tram was built in 1644 by Adam Wiebe. It was used to move soil to build defences. Other mining systems were developed in the 1860s by Hodgson, and Andrew Smith Hallidie. Hallidie went on to perfect a line of mining and people tramways after 1867 in California and Nevada. See Hallidie ropeway
Tramways are sometimes used in mountainous regions to carry ore from a mine located high on the mountain to an ore mill located at a lower elevation. Ore tramways were common in the early 20th century at the mines in North and South America. One can still be seen in the San Juan Mountains of the US state of Colorado. Over one thousand mining tramways were built around the world—Spitsbergen, Russia, Alaska, Argentina, New Zealand and Gabon. This experience was replicated with the use of tramways in the First World War particularly on the Isonzo Front in Italy. The German firm of Bleichert built hundreds of freight and military tramways. Strangely, Bleichert even built the first tourist tramway at Bolzano/Bozen, in then Tyrolian Austria in 1913.
Other firms entered the mining tramway business- Otto, Leschen, Breco Ropeways Ltd., Ceretti and Tanfani, and Riblet for instance. The perfection of the aerial tramway through mining lead to its application in other fields including logging, sugar fields, beet farming, tea plantations, coffee beans and guano mining. A resource on the history of aerial tramways in the mining industry is "Riding the High Wire, Aerial Tramways in the West", by Robert A. Trennert, University Press of Colorado, 2001.
In the 1920s the rise of the middle class and the leisure industry allowed for investment in sight seeing machines. The cable car to the top of high peaks in the Alps of Austria, Germany and Switzerland resulted. They were much cheaper to build than the earlier rack railway. One of the first trams was at Chamonix, while others in Switzerland and Garmisch soon followed. From this, it was a natural transposition to build ski lifts and chairlifts. The first cable car in America was at Franconia, New Hampshire in 1938. After the Second World War installations proliferated in Europe, America, Japan, Canada and South Africa. Many hundreds of installations have emerged in mountainous and seascape areas.
The aerial tram evolves again in latter decades—one tram in Costa Rica was built to move tourists above a rainforest, while one in Portland, Oregon, was built to move commuters. Presently, the mining role of tramways has lessened, though some still work, and moving people remains a starring role for the device.
Many aerial tramways were built by Von Roll Ltd. of Switzerland, which has since been acquired by Austrian lift manufacturer Doppelmayr. Other German, Swiss, and Austrian firms played an important role in the cable car business: Pohlig, PHB, Garaventa, and Mueller. Now there are three groups dominating the world market: Doppelmayr Garaventa Group, Leitner Group, and Poma, the latter two being owned by one person.
An escape aerial tramway is a special form of the aerial tramway that allows a fast escape from a dangerous location. They are used on rocket launching sites to offer the launch staff or astronauts a fast retreat. The tramway consists of a rope which runs from the launch tower downward to a protection shelter. On the launch supply tower several small cabs can be occupied by the launch staff or the astronauts. After a barrier is loosened these roll downward to the protection shelter. An escape aerial tramway exists on launch pads 39A and 39B at Cape Canaveral.
Some aerial tramways have their own propulsion, such as the Lasso Mule or the Josef Mountain Aerial Tramway near Merano, Italy.
While typically used for ski resorts, aerial tramways have been ported over for usage in the urban environment in recent times. The Roosevelt Island Tramway in New York City and the Portland Aerial Tram are examples where this technology has been successfully adapted for public transport purposes. In comparison to gondola lifts, aerial tramways provide lower line capacities, higher wait times and are unable to turn corners.[3]
One interesting offshoot of the aerial tram was the telpher system. This was an overhead railway, which was electrically powered. The carrier basket had a motor and two contacts on two rails. They were primarily used in English railway and postal stations. The original version was called telpherage. Smaller telpherage systems are sometimes used to transport objects such as tools or mail within a building or factory.
The telpherage concept was first publicised in 1883 and several experimental lines were constructed. It was not designed to compete with railways, but with horses and carts.[4]
The first commercial telpherage line was in Glynde, which is in Sussex, England. It was built to connect a newly-opened clay pit to the local railway station and opened in 1885.[4]
There are aerial tramways with double deck cabins. The Vanoise Express cable car carries 200 people in each cabin at a height of 380 m (1,247 ft) over the Ponturin gorge in France. The Shinhotaka Ropeway carries 121 people in each cabin at Mount Hotaka in Japan.
Despite the introduction of various safety measures (back-up power generators, evacuation plans, etc.) there have been several serious incidents on aerial tramways, some of which were fatal.
|
|
|
|||||||||||||
|
||||||||||||||||||||||||||||||||