Security and a way to logically stow the belongings and gear of hundreds of men in one room. There are other shots of this room on DA showing details of the mechanism involved. From what I could see from pictures, each miner stowed all his gear on the hanger arrangement which is attached to a really long chain/pulley arrangement leading to a numbered hook mechanism above the benches. I think I saw a picture of the little brass number plates somewhere. This arrangement would leave the rest of the room clear of clutter and would I imagine stop the casual thief from rifling the pockets while the workers were on their shift. Like I say it's just the impression I get from the pictures I've seen.