New Delhi, Feb 28 (IANS) A 100 metre-long concrete span being erected to pass over four rail tracks in south Delhi's Okhla area will be the longest segment so far used by the Delhi Metro for a bridge, an official said Sunday.

'The longest span built by the Delhi Metro Rail Corporation (DMRC) is being constructed on a bridge which will pass over the Indian Railways tracks near Okhla. This bridge will have a 100 metre-long span built over an operating railway line in Delhi,' DMRC spokesperson Anuj Dayal said.

The bridge on the Central Secretariat-Badarpur metro line is located between Okhla and Jasola metro stations. It will be 250 metres long and will comprise three spans - the two others are each 75 metre-long.

This metro line itself, connecting central Delhi to the capital's southeast fringes, is 20.16 km long. This metro corridor is scheduled to be completed by September 2010 ahead of the Commonwealth Games in October.

The Delhi Metro is using the 'cantilever construction (CLC)' methodology for making the bridge 'so that the rail traffic below the metro corridor is not hampered'.

About 130 workers are engaged in the construction of this concrete bridge.

Dayal said the bridge construction was especially tricky because it was being built on a very sharp curve with a 300 metre radius.

'The installation of the individual segments of the bridge on the curve is difficult as the railways traffic moving below cannot be obstructed during the construction,' Dayal explained.

Before this, the longest bridge segment the Delhi Metro had constructed was the 93 metre span built over the rail tracks near Pragati Maidan.