The benchmark BSE Sensex plunged by 303 points to dip below the 29,000-level during mid-session trading on Thursday after the Rail Budget failed to impress investors.

Besides, trimming of positions by cautious participants in view of monthly expiry in the derivatives segment, influenced the trading sentiment, brokers said.

The 30-share BSE Sensex dipped below the 29,000-mark by falling 303 points, or 1.04 percent, at 28,704.99 as selling activity gathered momentum.

Similarly, the National Stock Exchange index Nifty lost 77.35 points, or 0.88 percent, to 8,689.90.

Shares of companies related to the Railway sector came under pressure despite a series of measures proposed in the Rail Budget such as reviewing the wagon-making scheme to make it attractive for private investors.

Major losers on the Sensex were Texmaco Rail (-5.78 per cent), Titagarh Wagons (-5.97 per cent), Kalindee Rail Nirman (-5.89 per cent), Kernex Micro (-0.11 per cent), Stone India (-8.60 per cent), Simplex Castings (-3.72 per cent) and BEML (-0.43 per cent).

Besides, BHEL fell 2.94 per cent, Sun Pharma (-2.34 per cent), Infosys (-1.82 per cent), Bajaj Auto (-1.75 per cent), TCS (-1.32 per cent), Wipro (-1.16 per cent), Coal India (-1.03 per cent), ITC Ltd (-0.99 per cent) and Hindustan Unilever (-0.93 per cent), dragged down the Sensex.