The disaster struck on Friday, when a passenger train hit a stationary freight train, jumped the tracks and hit another passenger train passing in the opposite direction near the district of Balasore in the eastern state of Odisha.

Following nonstop efforts to rescue survivors and clear and repair the track, trains resumed running over that section of the line on Sunday night.

Until Monday evening, around 100 bodies were yet to be identified, a senior state health department official told Reuters.

Bijay Kumar Mohapatra, health director of Odisha, said authorities were trying to source iced containers to help preserve the bodies.

“Unless they are identified, a postmortem cannot be done,” Mohapatra said, explaining that under Odisha state regulations, no autopsy could be conducted on an unclaimed body until 96 hours had passed.

At state capital Bhubaneswar’s biggest hospital, the All India Institute of Medical Sciences (AIIMS), large television screens displayed pictures of the dead to help desperate families who were scouring hospitals and mortuaries for friends and relatives.

A detailed list was made of distinguishing features for each body, but relatives could first view photographs, however gruesome, to identify missing loved ones, a senior police official told Reuters.

The trains had passengers from several states, and officials from seven states – Assam, Bihar, Jharkhand, West Bengal, Tamil Nadu, Karnataka and Andhra Pradesh – were in Balasore to help people claim the bodies and take the dead home, the police official added.

India’s Railway Board has recommended that the federal Central Bureau of Investigation (CBI) take over the probe into the cause of the disaster while a separate inquiry led by A.M. Chowdhary, commissioner of railway safety for the southeastern circle, started on Monday.

The CBI team will reach the site on Tuesday and start its investigation.

Railway police filed a case of criminal negligence without naming any suspects.

A signal failure was the likely cause of the disaster according to preliminary findings, which indicated that the Coromandel Express, heading southbound to Chennai from Kolkata, moved off the main line and entered a loop track, a sidetrack used to park trains, at 128 kilometers per hour, crashing into the stationary freight train.

That crash caused the engine and the first four or five coaches of the Coromandel Express to jump the tracks, topple and hit the last two coaches of the Yeshwantpur-Howrah train, which was heading in the opposite direction at 126 kph on the second main track.