number of movable leaves

The number of movable leaves on a movable bridge is the total number of distinct sections of deck which are capable of moving in the course of normal operation. For example, a bascule bridge may have one leaf which spans the whole length, two leaves which meet in the middle and move separately, or four leaves when there are 2 sets of parallel leaves.

In the case of a folding bridge or a curling bridge, the individual segments are not counted separately.

The operating leaf is the unit of the count. Parallel sets can contain separate leaves, while the linked segments of a folding or curling assembly remain parts of that assembly.