The Bhopal Shatabdi at around 06:16 from New Delhi is the fastest and most comfortable train, although there are many trains. It gives you quite a good long day to see Agra, though it would be a shame not to spend the night and see fatephur Sikhri too, a deserted imperial city 25 miles away.

AC Chair car is fine, AC1 is great if you can afford it.

I'd pre-book as it gets full, try either www.cleartrip.com or www.irctc.co.in, both sites accept overseas credit cards. You'll find advice on using these at www.seat61.com/India.htm.

I agree with Man_in_seat_61 that Agra deserves an overnight, although not only for Fatehpur Sikri. One of the things photos don't really show you is how the Taj changes color with the light. You really should see it at sunset and sunrise.

I used cleartrip.com for my recent trip to India and it worked fine.

You can also try Taj Express in the morning around 7:00.

i would have concern about making such an exhaustive trip just a day or so after arriving... remember jet lague...

Hi
It is suggested that you book before you arrive. Rail Tickets at short notice is not generally available.

Regards

Sam