I worked in a salmon cannery in Anacortes, Wa. in the late 50's/early 60's.
We received box car loads of cans that were packed into very large
cardboard boxes that were on top of a pallet. The dimensions of the
box were the size of the pallet on the bottom and about 4 or 5 feet tall.
The pallets were loaded into the box cars with fork lifts and were stacked
two pallets high and pretty much filling the entire box car. They were
moved to the can loft above and along one side of the cannery and
stored in long lines on either side of a central aisle. During canning
operations the pallets of cans were moved to a machine in the loft
and slid off the pallet from the fork lift. I do not remember if the cans
were unloaded from the box bottom or top (tilted) by the machine -
but that machine fed the can line directly from the can loft to both
canning lines which were run to the actual canning machine and
rammed the salmon into the cans. The movement of the cans was
done in long open "tubes" similar to current automated canning. I
can probably find pics of the can loft part of the operation if needed.