Having snatched a 15-run first innings lead yesterday, Delhi batted out time to reach 395 for four with Rajat Bhatia making an unbeaten 157.
Bhatia, who faced 303 balls and hit 12 fours and two sixes during his innings, featured in two century partnerships -- with opener Shikhar Dhawan (87) and wicketkeeper-batsman Varun Kumar (54).
Delhi earned two points from the match to push their tally to six from three matches while Railways have two so far.
That will keep Delhi in good stead as they next face Madhya Pradesh who took the first innings lead over defending champions Mumbai in the second round last week.
Resuming at 101 for one, Delhi showed no urgency for runs but Railways somehow lacked the spirit in their bowling that was seen on the first day.
Both Harvinder Singh and J P Yadav, the new ball bowlers who had done the damage in the first innings went wicketless.
Left arm spinner Shankara Rao toiled hard, but his lone wicket of Dhawan cost him 116 runs from 48 overs.