Courtesy Gambhir's 40th first class hundred (136 batting, 245 balls) and his 207-run third-wicket stand with another centurion Nitish Rana (110, 158 balls), Delhi are in the driver's seat with an aim to log home full points.
This was after Assam were all out for 258, starting the day at 224 for 7 with skipper Ishant Sharma returning with best figures of 5 for 38 in 20 overs.
When Delhi started batting, it was yet another failure for Unmukt Chand (6), who was trapped leg before by right-arm medium pacer Krishna Das.
Dhruv Shorey's (1) stumps went for a walk off an Abu Nechim delivery.
However, Gambhir looked assured from the word go as he played some flowing off and cover drives. In all, he hit 21 boundaries.
When spinners were brought in, he showed his mastery with nimble footwork reaching to the pitch of the deliveries whenever Rahul Singh and Sarupam Purkayastha dropped short.
Young left-hander Rana, who had also hit a hundred against Assam last year, hit more boundaries square of the wicket.
His cut shots packed a real punch as he repeatedly pierced the off-side cordon.
Gambhir reached his hundred with two lofted boundaries off left-arm spinner Rahul Singh.
There was no celebration from the veteran southpaw, who was a picture of concentration. The best shot was a copybook straight drive off Krishna's bowling.
Rana reached 99 with a sweep shot and then completed his hundred off 150 balls with a single. He hit 18 boundaries before edging one off Abu Nechim's delivery.
Brief Scores: Assam 258 all out in 95 overs (Sarupam Purakayastha 66, Gokul Sharma 51, Ishant Sharma 5/38)
Delhi 269/4 (Gautam Gambhir 136 no, Nitish Rana 110, Abu Nechim Ahmed 3/39).
Railways vs Uttar Pradesh: Railways 1st Innings: 182 all out.
Uttar Pradesh 1st Innings: 250 all out (A Nath 75, RK Singh 42, A Singh 3/42).
Railways 2nd innings: 27/3 in 14 overs.
First Published: October 7, 2017, 6:11 PM IST