Off-spinner Powar claimed seven for 116, his second career-best performance in first-class cricket, to keep Rest in the hunt but the visitors' disastrous batting in the second knock undid his good work.
After Railways managed to put up 311, the last two wickets eking out 54 runs, for a handy lead of 88 in the first innings, the Rest capitulated to be all out for 137 at the Karnail Singh stadium.
Left-arm spinner Murali Kartik, who missed out on his maiden first-class hundred in the morning, picked 3-28 while offie Kulamani Parida grabbed 3-52, for a match haul of 7-113.
The Ranji Trophy champions now need to score only 50 runs to claim the coveted Cup their for second time in two seasons, having won it in 2003-04 at the same venue.
It was shoddy cricket from the Rest, even after making allowance for their inexperience and the dicey nature of the pitch.
With national coach Greg Chappell and National Selection Committee chairman Kiran More watching from the stands, the youngsters had all the reasons to put up their best display but they ended up marring their own reputation.
Most disappointing was Y Venugopala Rao (17) who, after playing a couple of elegant lofted on-drives, showed poor cricket in getting run out to Vineet Saxena who at forward shortleg showed good reflex to stop the ball and throw the stumps down in a flash. Rao's dismissal triggered the collapse, which came as a surprise as the Rest had looked in control until then.
Dheeraj Jadhav (42) and Suresh Raina (30) had added 55 runs for the second wicket and when Rao made a brilliant assault on Parida, hoisting him for two successive boundaries to long on, it seemed Railways had a match on their hands.
But from 98 for two, the Rest innings spiralled rapidly and the last wickets were lost for 39 runs.
True, the odd low keeping delivery and the sharp raising ones made batting difficult but there was no excuse for the lack of application.
Powar conceded as much after the match.
"Very disappointing, it was sheer lack of determination. It was a matter of defending but none of us were up to it," the 27-year old from Mumbai said.
On his own bowling performance, the diminutive Powar said lack of success on his previous two visits to the venue, with Mumbai in Ranji Trophy, made him that much more determined.
"It was my third visit here. I bowled a tight line and waited for the batsmen to make their mistakes," he said.
The track might have made life miserable for the batsmen but bowling was no easy either, as Powar had to roll his arm for over 40 overs to get his wickets.