Design, components, and operation

Operation and layout[edit]

Escalators, like moving walkways, are often powered by constant-speed alternating current motors^{[citation needed]} and move at approximately 1–2 feet (0.3–0.6 m) per second. The typical angle of inclination of an escalator to the horizontal floor level is 30 degrees with a standard rise^{[clarification needed]} up to about 60 feet (18 m). Modern escalators have single-piece aluminum or stainless steel steps that move on a system of tracks in a continuous loop.

"Crisscross" layout

"Multiple parallel" layout

"Parallel" layout

Escalators have three typical configuration options: parallel (up and down escalators side by side or separated by a distance, seen often in metro stations and multilevel motion picture theaters), crisscross (minimizes space requirements by "stacking" escalators that go in one direction, frequently used in department stores or shopping centers), and multiple parallel (two or more escalators together that travel in one direction next to one or two escalators in the same bank that travel in the other direction).^[1]

As a safety measure, escalators are required to have moving handrails that keep pace with the movement of the steps. This helps riders steady themselves, especially when stepping onto the moving stairs. Occasionally, a handrail will move at a slightly different speed from the steps, causing it to "creep" slowly forward or backward relative to the steps. The loss of synchronization between handrail and step speed can result from slippage and wear.^[2]

The direction of escalator movement (up or down) can be permanently set, or be controlled by personnel according to the predominant flow of the crowd, or be controlled automatically. In some setups, direction is controlled automatically by whoever arrives first, whether at the bottom or at the top (the system is programmed so that the direction is not reversed while a passenger is on the escalator).

Design and layout considerations[edit]

A number of factors affect escalator design, including physical requirements, location, traffic patterns, safety considerations, and aesthetic preferences. Foremost, physical factors like the vertical and horizontal distance to be spanned must be considered. These factors will determine the length and pitch of the escalator. The building infrastructure must be able to support the heavy components. The escalator should be located where it can be easily seen by the general public. In department stores, customers should be able to view the merchandise easily. Furthermore, up and down escalator traffic should be physically separated and should not lead into confined spaces.

Traffic patterns must also be anticipated. In some buildings, the objective is simply to move people from one floor to another, but in others there may be a more specific requirement, such as funneling visitors towards a main exit or exhibit. The escalators must be designed to carry the required number of passengers. For example, a single-width escalator traveling at about 1.5 feet (0.5 m) per second can move about 2000 people per hour. The carrying capacity of an escalator system must match the expected peak traffic demand, presuming that passengers ride single file. This is crucial if there are sudden increases in the number of riders. For example, escalators at stations must be designed to cater for the peak traffic flow discharged from a train, without causing excessive bunching at the escalator entrance.

In this regard, escalators help in controlling the flow of people. For example, an escalator to an exit effectively discourages most people from using it as an entrance^{[clarification needed]}, and may reduce security concerns. Similarly, escalators often are used as the exit from airport security checkpoints. Such an egress point would still generally be staffed to prevent its use as an entrance during times of light pedestrian traffic.

It is preferred that staircases be located adjacent to the escalator if the escalator is the primary means of transport between floors.^{[citation needed]} It may also be necessary to provide an elevator lift near the escalator for wheelchairs and disabled people. Finally, consideration should be given to the aesthetics of the escalator.