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Sliding Plug Doors

A door in which the panel or panels, in the open position, are positioned parallel to and outside of the car body. Plug doors can be of the sliding plug type whereby to open the door panel(s) first unplug by moving perpendicular to the car body and then open by moving parallel to the car body. Plug doors can also rotate open and closed in a parallelogram motion. Plug door systems can have either a single or double panel configuration.

The door leaf is hinged at one point by means of a carrier which travels over the main shaft during the sliding movement. The main shaft is connected on both sides to the roller cars which are plugged out the portal opening at the beginning of the opening movement. The door movement is programmed by the curve plate in combination with the roller on the carrier. The powering of the door is realized by means of the electromotor with gearbox in combination with the spindle, and functions according to the action / reaction principle.

The levers operating the roller car is kept in the “over centre” position in the door closed position, realizing the mechanical locking of the door, also in case the electrical power to the motor is lost.

This door system can have as well a double leaf as a single leaf configuration.

Principle of the action / reaction:


When the electromotor (1) is energized to open the door, the forces within the planetary gearbox (2) are transferred to the output shaft and the freely rotateable housing. Since the sliding movement is prevented, by the roller (3) within the curve plate (4) and therefore the spindle (5) prevented to rotate and the housing of the planetary gearbox is blocked by means of the belt (6) to the spindle, the output shaft will start to rotate. The rotation of the output shaft of the planetary gearbox will cause the toothed segment (7) to rotate which on its turn will pull the roller cars out the portal opening, creating the plugging movement. At the end of the plugging movement the roller within the curve plate becomes free to move in the sliding direction which results into the obstruction of the output shaft and the rotation of the housing of the planetary gearbox. By the rotation of the housing the belt powers the spindle to rotate, with the sliding of the door leaf parallel to the car body as a result.

The same principle is there during the closing of the door, first the sliding movement since plugging is prevented, and at the end followed by the plugging movement since this has become possible.

good sealing performance, appealing design, winter proof, simple and reliable system, more space available in the passenger area.

Range of application:
used on LRVs, trams, metros, regional trains.

In Europe, all LRVs, trams, metros and regional trains are equipped with this door type, which is also increasingly used in Asia.

Sources; apta.com, ife-tebel.nl,