Train travel in India:
(i agree with the both Swaroop Rao and Zachary Wasserman. And also for the most part with Ruchit Shah, except for the "Plus the train food is excellent" statement; i would say it varies on that count also. )
Practical Information:
An excellent guide (do read if you are not familiar with traveling on Indian trains)
http://www.seat61.com/India.htm
Booking/Reservation site:
http://www.irctc.co.in
some more scenic journeys would be:
- Darjeeling Mountain railway
http://www.dhrs.org/
http://en.wikipedia.org/wiki/Darjeeling_Himalayan_Railway
It is a UNESCO world heritage site; http://whc.unesco.org/en/list/944/
- Nilgiri Mountain Railway
http://en.wikipedia.org/wiki/Nilgiri_Mountain_Railway
Luxury Trains in India:
There are numerous, some are:
- Palace on wheels
http://www.rtdc.in/
- Maharaja express
http://www.rirtl.com/
- The Golden Chariot
http://www.goldenchariot.org/
- The Deccan Odyssey
http://www.thedeccanodysseyindia.com/
http://www.maharashtratourism.gov.in/mtdc/HTML/DO/index.html
There are quite a few more too.