The 74Es have a unique cargo configuration due to the five pallet spots in the rear of the main deck. The height of the fuselage on the main deck allows cargo to be stacked or arranged 16 feet high as opposed to a 63" high in the belly of a widebody jet, and the width of the upper door means that a specialized 20 foot pallet for large bulky items could be angled in the the main deck hold and occupy two positions upstairs (as opposed to a ~90" max width on the cargo deck).

There used to be a lot of oversize traffic to from FRA and HKG as well as LHR. Mostly auto parts and medical equipment to/from FRA and consolidated lots of consumer goods and electronics ex-HKG. A lot of it was immediately trucked to/from the US. Unfortunately traffic dropped off dramatically in the last few months and for the most part AC was transporting standard size loads on the upper deck, making the extra space uneccessary.