A huge amount of the noise came from those rattling springs in the pointless, never used, stretcher-bearing things. During an extremely long trip, I once wandered around with bits of blue roll jamming them up. Bliss - relatively.. Equally, on delivery trips to the thieves at Marshall's, the things were removed. Much quieter without them.
BTW: Many folks thought the wall cladding was sound-proofing. It wasn't. It was thermal insulation to prevent walking freight from getting frozen onto the metelwork.