A Central Railway inquiry into a ground cave-in near Turbhe and Kopar Khairane on the Trans Harbour line says the Maharashtra Industrial Development Corporation (MIDC) used an unapproved construction technique for an underground pipeline. The June 24 incident caused soil beneath the railway tracks to give way, disrupting suburban services for about two-and-a-half hours while rail teams carried out emergency restoration and safety measures.

According to the probe, MIDC had permission to lay underground utilities using a micro-tunnelling method, but allegedly deviated from the approved procedure by using a pipe-pushing technique. The inquiry attributes the cave-in to weakened soil supporting the tracks as a result of the method used. Railways also cites additional issues related to the execution, including inadequate safety precautions and supervision lapses.

Central Railway has initiated disciplinary action, including a chargesheet for a railway supervisor, and has started penalty proceedings against MIDC. Railways says it is tightening monitoring of nearby infrastructure works. The project is reported to be partly completed and MIDC has been given time to finish remaining work, with an expected revised completion date of January 2026.