Mumbai: The BSE benchmark Sensex on Thursday gained over 68 points to close at 17,700.91 on fresh buying in blue-chips at lower levels.

The increase was bolstered by a firm tend in the Asian region and higher openings in Europe on easing of crude oil prices.

Besides, the Railway Budget this afternoon unveiled plans for adding new railway lines - a positive for infrastructure. The gains were led by stocks in the financial, FMGC and auto sectors.

The Bombay Stock Exchange benchmark index Sensex shuttled between the day's high of 17,812.44 and a low of 17,469.97, before ending 68.50 points up at to 17,700.91.

In a similar fashion, the broad-based National Stock Exchange index Nifty rose 40.85 points to 5,303.55, after moving between 5,338.20 and 5,232.75.

Trading sentiment improved as the Survey, tabled in the Parliament, said the economy would to grow at 9 per cent in 2011-12, from the projected 8.6 per cent this fiscal.

Among the 30 index components, 13 stocks closed with gains while 17 ended lower. The most-heaviest Reliance Industries was up on favourable corporate reports.