The ladder of the early escalator was made of wood. Since 1987, when a fire broke out at the London underground railway station, most of the wooden steps that were still in use have been converted to metal. The steps of the modern escalator are made of metal, and each step is provided with a triangular bracket. The bottom of the bracket is provided with two shafts. The two wheels on each side walk on different tracks, so as to maintain the level of the ladder by changing the distance between the tracks. The wheel above each step bracket is hinged. Under the escalator at the top of a motor drives the hinge plate, moving the step. When the steps to at the end of the escalator, will turn into row to let passengers leave, then turn down the bottom plate, and to another direction, become an endless circle. Some new side escalators on the glass, can clearly see the mechanical structure. As for the handrails on both sides, is made of plastic, in addition to drive the wheel, and to maintain the speed and the same step.
Most of the escalators are straight. In 1985, the MITSUBISHI electric motor of Japan invented the curve for the first time. In addition to saving space, spiral staircase is also very artistic effect. In addition, some escalators can be changed back into the middle section. This can reduce the use of a very long staircase passengers fear of height, but also can be more flexible with the building