A Locked Elevator cannot be operated until it is unlocked with a switch or access card.

Create an elevator. Place an L[0,Channel] in the elevator sector. Then place a Switch, or Access Switch (#130 or #170) tagged [ActivationSound,Channel] somewhere in the map. It will be used to unlock the elevator (the elevator can be toggled between locked/unlocked with a regular Switch). If you use an Access Switch, place an Access Card (#60) somewhere. A value of 212 is the standard choice for an Access Switch's ActivationSound. To change the colours of the Access Switch and Card, adjust their palettes: [0] = blue, [21] = red, or [23] = yellow.