Mumbai piled the pressure on Railways as they amassed a massive first innings total of 570 all out on the second day of a Group A Ranji Trophy tie at the Wankhede Stadium on Saturday.
After Sachin Tendulkar and Ajinkya Rahane had hogged the limelight on the first day with their spectacular centuries, Abhishek Nayar impressed on the second with an unbeaten 107 off 164 balls.
Railways found themselves in a spot of bother losing both their openers, Shivakant Shukla (18) and Amit Paunikar (9) with just 31 on the board.
Captain Sanjay Bangar (36 not out) and Nitin Bhille (21 not out) restored some parity with an unbeaten 55-run stand to take Railways to 86 for two at the end of the day's play.
Mumbai resumed the proceedings on an overnight score of 344 for four. Rahane could only add 24 runs before he was trapped in front of the stumps by Krishnakant Upadhyay.
Nayar then batted brilliantly with the tail as skipper Ajit Agarkar played a cameo, scoring 20 off 35 balls.
Spinner Ramesh Powar (41) played a gritty hand and played a key role in taking Mumbai to their mammoth total.
He stitched a 63-run partnership with Nayar for the eighth wicket, ensuring Mumbai crossed the 500-mark.
Anureet Singh and Shukla were impressive with ball taking three wickets apiece while veteran spinner Murali Kartik accounted for two.
Agarkar was on target for Mumbai with the ball taking both the wickets to fall in the Railways innings.