A wall collapse inside the Pernem tunnel on Thursday morning has paralysed the services on Konkan Railway (KR) and the trains are now being diverted via Miraj-Pune route. A KR note said eight trains will be diverted till August 20.

Old-timers and KR records recall how Pernem tunnel has always been a problem, which alone had delayed the entire KR project for five months. KR has 91 tunnels, adding up to 84 km in length. However, tunnels totalling 3,500 metres in length on weak soil, mainly in Goa and Karnataka, posed the most problems during construction. Recalling the construction days, former managing director Dr E Sreedharan said, "The soil in the tunnels became like toothpaste. The unexpected geology and soft soil in Pernem and Old Goa tunnels were leading to accidents and collapses."