PV:

Please read my post again: It sez .001125 inches PER INCH! That's
..0135" per foot.

The reason for this relatively small deflection is to keep the power
requirements low on the trolley drive when loaded to capacity. Don't
forget that some of these cranes have large capacities and spans. In
my sphere of responsibilities were 50 ton,132 ton, and 200 ton capacity
cranes, all with a span of 100 feet. The small deflection also reduces
the bounce when inching or spotting a load for assembly.

The deflections you state are for building floors; with the standard
being L/360 and L/480.

Wolfgang