Escalators 101

An escalator is one type of vertical transportation that is basically in the form of a moving staircase that carries people through floors of a building. An escalator consists of a motor driven chain made up of individually linked steps on a track which cycle on another set of tracks that help to keep them horizontal. 

Elevators aren’t practical in every space, thus creating the need for escalators. Primary areas of usage are: shopping malls, arenas, department stores, convention centers, hotels, airports, and other public buildings.

Escalators have the ability to move large numbers of people and can easily be placed where a typical staircase would be. Unlike elevators, there’s no waiting interval, unless there is very heavy foot traffic. Another benefit to the escalator is that they can guide people towards special events or main exits. There are also options to have escalators weatherproofed in order for them to be used outside. Whereas most forms of transportation become useless once they break down or lose power, escalators can be used as a functioning staircase, making it a very useful machine even when not connected to power.

 Operation and Layout: 

  Escalators are typically at a 30-degree angle from the ground, travelling at a whopping 1:2 feet per second. Most elevators contain single-piece aluminum or stainless-steel steps that move on a system of tracks in a continuous loop.

Escalators can be configured in more ways than one; to be exact, there are three. The first way is “parallel.” Parallel escalators are escalators that are nearby each other. For example, up and down escalators. This type of escalator is usually found in metro stations and shopping malls. The second way an escalator is configured is a, “multiple parallel escalator.” These are banks of more than one escalator moving in the same direction parallel to banks going in the other direction. The third type of escalator is called a “crisscross.” These are escalators that are going in one direction that are stacked with escalators going the opposite direction, oriented adjacent but perpendicular. These are the escalators that you typically see in department stores. 

The United States, like most countries, require escalators to have moving handrails to keep pace with the movement of the steps as an extra safety measure. The moving handrails help riders keep steady when stepping on and off the moving stairs. Sometimes slippage and normal wear and tear can cause the handrail to move at a slightly different speed than the steps. Depending on the escalator, the up and down movement can either be permanently set, automatically set or controlled manually depending on crowd flow.

 Design and layout:

  Of course, there are many physical factors that need to be determined before building an escalator in a certain area. Important factors such as location, traffic patterns, aesthetics, physical requirements and safety considerations are very important to keep in mind before starting a build. Physical factors, like the distance to be spanned, end up determining the length and pitch of the escalator, while other factors such as the infrastructures ability to provide power and support must be considered. Other important considerations include how upward and downward traffic is separated and load/unload areas are important considerations. 

The last factor that needs to be considered is the traffic pattern that will occur in the place of the escalator. Some escalators only need to move people from one floor to the next but there are escalators that need to funnel visitors towards exits and exhibits, meaning that most escalators have temporal traffic patterns. The visibility and accessibility of the escalator to traffic is also something to be aware of. Additionally, designers need to account for the amount of traffic to be expected on each device. Another factor that depends on the traffic of an escalator is the carry capacity. The escalator’s carrying capacity system is typically matched to the expected peak traffic demand. An example of this are escalators at transit stations. These escalators must be designed to cater to the peak traffic flow while making sure there is no excessive bunching at the escalator entrance. The most important job of an escalator is to help manage the flow of people and foot traffic. While many escalators are often built next to staircases in order to allow alternate travel between floors, there are also escalators that deliver passengers to one exit which makes it impossible for anyone to enter at the exit of the concourse. 

 Landing Platforms:

 What is a landing platform? Landing platforms are the two platforms located at both ends of the escalator. The platforms house the curved section of the tracks and also the gears and motors that operate the stairs.  The top platform typically contains the motor assembly and main drive gear, while the bottom holds the step return idler sprockets. Both of these sections are also responsible for anchoring the ends of the escalator truss. Along with those components, the platforms have a floor and comb plate. The floor plates provide an area for passengers to stand on before stepping onto the moving stairs, levelled with the rest of the floor and hinged to allow easy maintenance access, while the comb plate lay between the stationary floor plate and the moving steps. The comb plate is often referred to as ‘cleats’ because they mesh with matching cleats on each step, resulting in their comb-like appearance. These interlocking cleats help minimize the gap between the stairs and landings, thus preventing objects and people from getting caught in it. 

 Truss:

  The truss is the hollow metal structure that bridges the lower and upper landings, composed of two side sections joined together with cross braces across the bottom and just below the top. The ends of the truss are attached to the top and bottom landing platforms via steel or concrete supports. It carries all the straight track sections connecting the upper and lower sections.

 Balustrade: 

 The balustrade is what supports the handrails of the escalator, made out of metal, sandwich panels or glass while also providing additional protection for the handrail and passengers. At the end of the balustrade, some escalators feature direction arrow buttons, while all of them contain the escalator’s on/off buttons. Moving walkways are another machine that uses balustrades the same way.

 Tracks: 

  The track system is built into the truss in order to guide the step chain. The step chain continually pulls the steps from the bottom platform and back to the top in an endless loop. The first track of the escalator is responsible for guiding the front wheels while another guides the back wheels of the steps. The positioning of these tracks causes the steps to form a staircase as they move out from underneath the comb plate. The tracks are their maximum distance apart when they are along the straight section of the truss. This configuration is necessary because it forces the back of one step to be at a 90-degree angle in order for it to be relative to the step following behind. Without this right angle, the steps wouldn’t be able to form a staircase.  The two tracks converge at both the bottom and top of the escalator making the back wheels of the steps into a straight line. Once this happens, the stairs lay flat one after another, so they can easily travel around curved section of the track. A responsibility of the tracks is to carry the steps down along the underside of the truss until they get to the bottom landing where they then pass through another curved section of the track before finally exiting the bottom landing. Once all of this happens, the tracks separate, and the steps once again begin forming their staircase. This whole cycle repeats continually as the escalator is being used.

 Steps:

The solid steps of an escalator are made using one piece, die -cast steel or aluminum. Most stairs feature a yellow demarcation line to indicate their edges. Both the riser and tread on each step is cleated with comb-like protrusions that mesh together with the bottom and top platform comb plates and the following steps in the chain.

 Handrail:

When riding an escalator, passengers need something to hold onto for stability and safety. This is where the handrail comes in. The handrail is pulled on its own track by a chain that is connected to the main drive with a series of pulleys. The pulleys help to keep the handrail to travel at the same speed as the steps. The rail has four sections, the slider, the tension member, the inner components and the outer layer. In the center of the rail is a “slider” or “glider ply.” The “slider” is a layer of synthetic cotton that allows the rail to move smoothly with the track. Providing the handrail with flexibility and strength is the “tension member”. This section lies on the slider and is made out of steel or flat steel cables. On top of the tension member lies the inner components. The inner components are made with chemically treated rubber in order to prevent the layers from separating. Lastly, is the outer layer, which is what we see. The outer layer is the cover of the rail made with a blend of rubber and polymers. Covers are made in order to resist deterioration from environmental conditions, mechanical wear and tear and vandalism. 

 Safety:

As with any type of machinery, safety is a big concern with escalators. Escalators are very powerful machines and they can easily become entangled with clothing or other items. It is possible that these entanglements can result in injury or death. In fact, most escalators in India are made with “sari guards”. These are added to the escalator because most women wear saris. Saris can easily get tangled in an escalator, with no guard, causing injury. Another factor to keep in mind is footwear. Shoes made with a softer material such as sandals and crocs are especially at risk of getting caught in an escalator. Some other safety features that escalators can have are fire detection devices and suppression systems. Like most machinery, escalators can over heat. To limit this risk, spaces that contain motors and gears usually have additional ventilation. They can also have small, clean agent, automatic extinguishing systems for fire protection. 

  This article was created to provide you with some new knowledge regarding escalators. We see this type of machinery everywhere but not many people realize how much goes into one escalator.  We hope you enjoyed reading Escalators 101 and have learned something new!