Very interesting topic sir. This reminds me my Train journey in II reservation class with wooden sleepers. In summer in order have cool water, my father use to buy one Surahi (Earthe pot) ~ Rs 5-10 those days. I am attaching a pic from inet for ref. This was for us a game to save Surahi until we reach destination home in remote village to have cold water. Some times success and some time disposal :-) but those days were better than plastic age. Thanks for this tribute to remember those fingers who quenches our thirst and made pleasant travel.