Cheers Superalbs - I'll post another later today.
I took the Gatiman Express from Nizamuddin to Agra for the Taj Mahal a few years ago. (I was working in New Delhi). I'd been in in Varanasi the day before after an overnight sleeper train from New Delhi. However I was waitlisted for the sleeper train to Agra from Varanasi and missed out on a bed/bunk. So faced with an overnight journey in a seat I opted to get a Taxi to the airport and get a cheap flight back to New Delhi as my accommodation was all paid for the whole 2 week work trip. The next morning I asked the Reception at the Hotel if tickets were available but they said sold out. However the guy assured me that there would be people selling tickets at the station in order to make a small profit on the ticket. So I managed to pick a ticket up at the station for the return journey.
By the way Superalbs, I enjoyed your Youtube journey on the Worlds worst Sleeper Train in Sri Lanka! Good to put a face to a name.