Although certain managers claim there's official, enforceable policies (ranging from as few as 35-minutes to 50-minutes), there aren't. Nor does the union recognize production, anyway. Piece count and load quality vary heavily among trailers. We receive trailers that are 100% bulk, and one hub will divide all the large, heavy packages into one trailer and smaller pieces (much of which could be containerized) into another. There's other factors affecting the time it takes us to unload: if there's too much bulk, an egress problem will occur in which production is halted; with more than two dozen active unload doors, a single belt will frequently get overloaded, thus slowing down production from the input, etc. I last worked the preload last winter (I'm full-time now, I bump onto the sort when I'm on extended layoff) -- between then and now management has begun heavily enforcing the use of load stands + the adjustment of the extendo. This further slows the process down (not by much but every minute counts).
In the end, the company can only ask for a fair days work for a fair day's pay. It can discipline the unloaders for delay of load, but it's a heavy burden to prove -- much easier to move the "culprit" to loading (or elsewhere).
BTW, I've toured many centers (CHSP participation) and since the widespread implantation of extendos (after the retirement of the drop-frames), it has not been common practice to double trailers up, unless an unloader would otherwise be idle.
