A vertical rear door for a single-face station which has a pressurized volume and which station is used to produce corrugated cardboard. The door consists of a panel with an outer dimension slightly smaller than the inner dimensions of the door frame in which it is received. The whole periphery of the panel of the door is provided with peripheral seals resting on the inner periphery of the framework. An interlocking arrangement includes at least a hook mounted to extend in a vertical plane from the inner surface of the panel of the door and liftable so that it can move in a vertical plane by means of a lifting arrangement. The hook engages an interlocking axle which is mounted permanently on the door frame and the front part of the inner notch of the hook has a forward curvature to surround a substantial portion of the axle when the hook is engaged thereon. The hook also has a front cam surface which will cause lifting of the hook to allow it to ride up over the axle until the inner notch is received on the axle during closing of the door.

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