An escalator is a conveyor transport device to transport people, consisting of a staircase whose steps move up or down on tracks which keep the surfaces of the individual steps horizontal. Most escalators also have moving handrails which approximately keep pace with the movement of the steps. The direction of movement (up or down) can be permanently the same, or be controlled by personnel according to the time of day, or automatically be controlled by whomever arrives first, someone at the bottom or at the top (of course the system is programmed such that the direction is not reversed while somebody is on the escalator). In the last two cases there has to be an alternative nearby.

A moving sidewalk, moving walkway, slidewalk, travelator, travellator or trav-o-lator is a slow speed conveyor belt to transport people; they can walk along it or stand; it is like a horizontal escalator. They are often applied in pairs, one for each direction.

They are often used in airports where there is a long distance to walk between terminals, and in metro stations.

The speed is usually 3 km/h, but there is a high-speed version with a speed of 9 km/h at Gare Montparnasse station in Paris.

An inclined moving sidewalk, movator or moving ramp is used in airports and supermarkets to move people to another floor with the convenience of an elevator (people can take along their suitcase trolley or shopping cart) and the capacity of an escalator. The carts have either a brake that is automatically applied when the cart handle is released, or specially designed wheels that secure the cart within the grooves of the ramp, so that it doesn't roll uncontrollably down the ramp.

History

In 1892, Charles A. Wheeler patented ideas for the first practical moving staircase, though it was never built. Some of its features were incorporated in the prototype built by the Otis Elevator Company in 1899.

Jesse W. Reno invented the first escalator and installed it as an amusement ride at Coney Island, New York in 1897. Charles Seeberger further developed it and joined the Otis Elevator Company in 1899, and together they produced the first commercial escalator which won a first prize at the Paris 1900 Exposition Universelle in France. The Otis escalator was modeled after Mr. Seeberger's invention. The company later combined the best aspects of both the Reno and Seeberger inventions and in 1921 produced an escalator of the type used today. These improvements in design brought the escalator into extensive use in department stores and banks and in metropolitan railroad and subway stations.

The German company Orenstein & Koppel (O&K), would also become a major player in escalator design and manufacture.

Design

Escalators in the London Underground used to have wooden steps, but this was changed after the fire at King's Cross St. Pancras tube station in 1987. Old escalators with wooden steps are still in use in some places, however, such as the Tyne Cyclist and Pedestrian Tunnel in Tyne and Wear, England and the Macy's department store in New York City. Modern escalators have metal steps in a continuous loop that move on tracks. Escalators are typically used in pairs with one going up and the other going down. Some modern escalators in stores and shopping malls have glass sides which allow their workings to be viewed. Although most escalators are straight, some shopping malls use curved versions. Most escalators nowadays require people to move on and off in the same direction as the steps are moving. At Earls Court, London, UK, the first escalator installed on the London Underground required people to move on and off from the side of steps at each end of their journey.

Spiral escalators

A spiral escalator would take up much less horizontal space than the usual straight escalator flight. However, early attempts at spiral designs ended in failure, such as one constructed by Reno in conjunction with William Henry Aston at London's Holloway Road Underground station in 1906. It was dismantled almost immediately and little of the mechanism survives.

Mitsubishi Electric Corporation has developed and manufactured curved and spiral escalators since the 1980s.

Usage

When using escalators, passengers who wish to stand and let themselves be carried up or down should stand on one side to allow more impatient users to walk past them. However, which side varies from place to place, as does the degree of observance—this rule is more likely to be adhered to on, for example, the long escalators of an underground transport system than in a department store. On the London Underground and Washington Metro, standers are asked to keep to the right. Within the United States, the left side of a moving sidewalk is reserved for walking; the right side is for standing. In some other countries this custom is reversed, but not necessarily corresponding with the rules of the road: in London and Hong Kong one stands on the right, in Australia on the left. In the Montreal Metro, there is no rule, as passengers are supposed not to walk on the escalators, a rule scarcely observed and not at all enforced.

There have been various reports of people actually falling off a moving escalator or getting their shoe stuck in part of the escalator. A few fatal accidents are known to have involved escalators and travelators: Sally Baldwin, a professor of the University of York was crushed to death at Tiburtina Station in Rome on 28 October 2003 after a travelator collapsed and she was pulled into the cogwheels. In another incident, Francisco Portillo, a Salvadorian man living in Boston died after getting his hood stuck in an MBTA escalator on 21 February 2005.

Longest escalators and systems

In Hong Kong, tens of thousands of commuters travel each work day between Central, the central business district, and the Mid-levels, a residential district hundreds of feet uphill, using a long distance system of escalators and moving sidewalks called the Central-Mid-Levels escalator. It is the world's longest outdoor escalator system (not a single escalator span), at a total length of 800m. It goes only one way at a time; the direction reverses depending on rush hour traffic direction. The Ocean Park in Hong Kong also has a long escalator systems connecting two parts of the Park. In the Times Square shopping centre in Causeway Bay there is a bank of four curved escalators, whereby the top of each escalator is approximately facing 180 degrees from the bottom of the same escalator - by necessity the undersides of these escalators are thicker as the step return mechanism needs to be more complex than on a straight escalator.

The longest escalator in the Western Hemisphere is at the Wheaton station of the Washington Metro subway system. It is 508ft (155m) long.

However, the metro systems in several cities in Eastern Europe (including St. Petersburg, Kyiv and Prague) have Soviet-era escalators up to approximately 330ft (100m) long. Those at the Nám
stí Míru station in Prague were rebuilt to the same length in 1998–9 by ThyssenKrupp.