The Indian railway system is awesome. It handles over 7 billion passengers in the world each year making it most probably the largest mass transportation system in the world*. These passengers as well as millions of tonnes of frieght travel over 64,000 km of tracks in one of 9,000 locomotives. Finally these lucky travellers have over 7,000 stations to choose from. The railway has over a million regular employees making it one of the worlds largest single employer too. Managing this system is mind boggling but the Indians haven't balked at this task. They have grasped it with both hands and created an online platform where one can book seats on any one of the 10,000 daily trains** through the seven different classes. But that's not all either, 50% of the reserved train tickets are held in an emergency quota and only released for sale one day before travel making the online rush for tickets a daily crush for any system. But it works and it works well. Could this be the world's largest operable online platform?*
Again, that's not all. If one changes their mind they can cancel beforehand and receive about 95% of the ticket cost back and even if one doesn't cancel and not travel one is eligible for some refund.
But no system is perfect and my train is delayed by 4 hours... :(
* Be great if someone can verify these. ** From wikipedia. Trust it at your own peril.