New Delhi: The Delhi Metro Rail Corp (DMRC) will build over 100 cross passages between parallel underground tunnels in its upcoming Phase 3 line. A cross passage is generally a small path which connects two tunnels through a walkway varying between 6 and 10 metres. "Two tunnels are generally built parallel to each other for up and down movement of trains and these cross passages allow people to move from one tunnel to another in case of emergency." a DMRC statement said. "There will be a cross passage after approximately every 240 metres inside every underground tunnel. Cross-passages are built with reinforced concrete. They are provided to serve two primary purposes - emergency escape and maintenance work." The present Delhi Metro network has 108 cross passages.