Which door is referred to as the trailing door in a center-opening system?

In a center-opening elevator door system, the trailing door refers to the door on the opposite side of the drive door, which is the door that is mechanically activated to open first by the elevator's drive system. When the elevator arrives at a landing, the drive door, or the leading door, is the one that opens first to allow passengers to enter or exit. The trailing door follows shortly after, remaining in a closed position until the drive door is in motion.

Understanding this terminology is crucial because it assists in identifying and troubleshooting door operation mechanisms within the elevator system. The terms used to describe the doors help technicians and installers ensure that they are making the correct repairs or adjustments, which is essential for the safe and efficient operation of the elevator. This distinction is especially important in maintenance and safety protocols.