Mumbai authorities were searching for clues as to who was behind Tuesday's seven coordinated bomb blasts aimed at the vital railway artery that serves the city of 17 million.
700 people were wounded, many were in critical condition, so authorities expect rising of the death toll, the AP reports.
Suspicion immediately fell on Muslim militants fighting New Delhi's rule in Kashmir.
Pakistan, which denies Indian charges of tacit support for the militants, condemned what it labeled a "terrorist attack".
Authorities were running more buses on routes where train services had yet to resume, according to Reuters.