Cleartrip.com is one of the pioneer air travel option aggregators. Recently, cleartrip extended its services to train search also. Thats a great news for candidates planning their GD PI schedule. Now, they have one site where they can look for cheapest air fares and at the same time search for trains available, seat availability and applicable fares. Cleartrip does not allow you to book your tickets though, but the site is lightning fast and can help you decide upon a train before you head on to irctc.co.in for ticket booking.
All these features are neat but I think it would be great if cleartrip can provide comprehensive search results i.e. list all air and train options on one page instead of searching for them separately. That said, whatever is being offered by cleartrip is great and their effort should be applauded.