Parsik tunnel is a railway tunnel which cuts across the Parsik Hill in Thane, Maharashtra, India. This tunnel lies on Mumbai-Chennai mainline. This reduced the distance between Thane and Diva to 7 km (4.3 mi) from formal 9.6 km (6.0 mi). This tunnel is 1.3 km (0.81 mi) in length made a landmark of first mile long tunnel constructed by Indian Railways. This tunnel is used by all trains skipping and . This tunnel is one of the oldest tunnel in Asia. Once it was the third largest tunnel in Asia. Electric powered train operate through this tunnel and the tunnel has double lines. Two new tunnels have been planned across the Parsik Hill. One of these will be parallel to the existing tunnel for fast suburban train and freight trains and the second one between Kalwa and Mumbra stations.