Laxmi Ratan Shukla's men reach the last four stage for the first time since 2006-07 season.
Chasing a target of 271, Railways, who began the day from overnight score of 117 for 3, were all out at 222 n 83.3 overs.
After a later start due to overcast conditions and rain, Arindam Ghosh (50) and Nitin Bhille (5) came out to bat for Railways on Sunday.
Railways lost wickets at regular intervals as their innings came to an end at 222.
Shib Sankar Paul, Ashok Dinda and Sourav Sarkar picked up two wickets each while skipper Laxmi Ratan Shukla took three wickets for Bengal.
Bengal scored 317 in their first innings before bowling out the visitors at 314, taking slim lead of three runs. Bengal posted 267 on the scorecard in the second innings.
Bengal will now face Maharashtra in their semi-final clash at Indore while Punjab will take on Maharashtra in the other last-four encounter.
Cricketer Manoj Tiwary tweeted: " Congratulations 2 our Bengal cricket team 4 reachin d semi finals of RANJI TROPHY. Well done boys."
--IBNS (Posted on 13-01-2014)