A monorail is a rail-based transportation system based on a single rail, which acts as its sole support and its guideway. The term is also used variously to describe the beam of the system, or the vehicles traveling on such a beam or track. The term originates from joining the words mono (one) and rail, from as early as 1897, possibly from German engineer Eugen Langen who called an elevated railway system with wagons suspended the Eugen Langen One-railed Suspension Tramway (Einschienige Hängebahn System Eugen Langen). The transportation system is often referred to as a railway. Colloquially, the term “monorail” is often used erroneously to describe any form of elevated rail or peoplemover. In fact, the term solely refers to the style of track, not its elevation.
Monorail systems have found shared applications in the transportation market in airport transfer and some medium capacity metro systems. To differentiate monorail systems from other transport modes, the Monorail Society further clarifies the definition of a monorail such that the beam in a monorail system is narrower than the vehicle.
Similarities
Monorails are often but not exclusively elevated, sometimes leading to confusion with other elevated systems such as the Docklands Light Railway, Vancouver SkyTrain and the JFK AirTrain. Monorail vehicles are often at first glance similar to other light rail vehicles, and can be both manned and unmanned. Monorail vehicles can also be found in singular rigid format, articulated single units, or as multiple units coupled into ‘trains’. In common with other advanced rapid transit systems, some monorails are driven by linear induction motor. In common with many dual rail systems, the vehicle bodies are connected to the beam via bogies, allowing curves to be negotiated.
Differences
Unlike some trams and light rail systems, modern monorails are always partitioned from other traffic and pedestrians. Monorails are both guided and supported via interaction with the same single beam, in contrast to other guided systems such as Rubber-tyred metros, such as the Sapporo Municipal Subway; or guided buses or trams, such as Translohr. Monorails also do not use pantographs.
Maglev
Under the Monorail Society beam width criteria, some but not all maglev systems are considered monorails, such as the Transrapid and Linimo. Maglevs differ from all other monorail systems in that they do not (normally) physically contact the beam.
The first monorail was made in Russia in 1820 by Ivan Elmanov. Attempts at creating monorail alternatives to conventional railways have been made since the early part of the 19th century. The earliest patent was taken out by Henry Palmer in the UK in 1821, and the design was employed at Deptford Dockyard in South-East London, and a short line for moving stone from a quarry near Cheshunt, Hertfordshire to the River Lea. The Cheshunt line is notable as it was the world’s first monorail to carry passengers, as well as the first railway line to be opened in Hertfordshire.
Around 1879 a “one-rail” system was proposed independently by Haddon and by Stringfellow, which used an inverted “/\” rail. The system was intended for military use, but was also seen to have civilian use as a “cheap railway.”
Early designs centred on use of a double-flanged single metal rail alternative to the double rail of conventional railways. Wheels on this rail would both guide and support the monorail car. A surviving suspended version is the Wuppertal monorail. Into the 1900s, Gyro monorails, with cars gyroscopically balanced on top of a single rail, were tested, but never developed beyond the prototype stage. The Ewing System, used in the Patiala State Monorail Trainways in Punjab, India, relies on a hybrid model with a load-bearing single rail and an external wheel for balance. One of the first systems put into practical use was that of French engineer Charles Lartigue, who built a monorail line between Ballybunion and Listowel in Ireland, which was opened in 1888 and closed in 1924 (due to damage from Ireland’s Civil War). The Lartigue system uses a load-bearing single rail and two lower, external rails for balance, the three carried on triangular supports.
Possibly the first monorail locomotive was a 0-3-0 steam locomotive.
From 1950 to 1980 the monorail concept may have suffered, as with all public transport systems, from competition with the automobile. Monorails in particular may have suffered from the reluctance of public transit authorities to invest in the perceived high cost of un-proven monorails when faced with cheaper mature alternatives. There were also many competing monorail technologies, splitting their case further.
This high cost perception was challenged most-notably in 1963, when the ALWEG consortium proposed to finance the construction of a major monorail system in Los Angeles, in return for the right of operation. This was turned down by the city authorities in favour of no system at all, and the later subway system has faced criticism as it has yet to reach the scale of the proposed monorail.
Several monorails initially conceived as transport systems survive today on revenues generated from tourism usage, benefitting from the unique views offered from the largely elevated monorail installations.