The death toll from India's worst train accident in years rose to 146 on Monday after rescuers used cranes to lift the last of the twisted metal wreckage to check for bodies underneath.

About 2,000 workers were clearing the tracks and checking for damage to the rail line in hopes of resuming traffic through one of India's busiest railway junctions by Monday evening, railway official Amit Kumar said.

The government called for an investigation into what caused the accident, promising to punish anyone found responsible.

The passenger train was about midway through a 27-hour journey between the cities of Indore and Patna when it slid off the tracks at 3:10 a.m. Sunday. The impact was so strong that one of the coaches landed atop another, crushing the one below. Passengers were flung from their beds.

Doctors attend to the victims of Sunday’s train derailment in Pukhrayan at a government hospital in Kanpur. More than 200 people were hurt. (Jitendra Prakash/Reuters)

"I heard a loud noise," passenger Satish Mishra said. "The train then sped up, and all the coaches derailed."

Rescue workers, soldiers and members of India's disaster management force pulled out people trapped inside the twisted metal and overturned coaches near Pukhrayan, a village outside Kanpur about 400 kilometres southeast of New Delhi.

They used cutting torches to pry open cars and cranes to lift coaches from the tracks, moving carefully to avoid injuring those trapped inside. By Monday afternoon, they had lifted the last of the 14 wrecked cars from the tracks, finding no more bodies beneath.

Family killed en route to wedding

The accident killed at least 146, according to state official Debasish Panda. Doctors said 116 of the victims had been identified.

Roughly 226 people were hurt, including 76 with serious injuries, according to local police Insp.-Gen. Zaki Ahmad. Medical teams provided first aid near the site, while those in more serious condition were moved to hospitals.

Anxious relatives searched for missing family members among the injured and the dead at hospitals in Kanpur.

Whoever I tried to look for is dead. - Ramanand Tiwari

At the accident site, some sifted through torn and broken luggage scattered across the ground in hopes of finding clues to where someone might have been at the time of the crash.

"I am looking for my brother," said Ramanand Tiwari, according to the Press Trust of India news agency. "He may have changed his seat ... we have searched everywhere."

Nearby, a man sobbed after seeing the bodies of three family members who had been travelling together to a wedding.

"Whoever I tried to look for is dead," Nirmal Verma told PTI. "I haven't found my mother ... I fear I will find her in the same condition."

Train safety a major issue in India

Some railway officials told local media they suspected faulty tracks caused the derailment.

"We haven't seen an incident like this in Indian Railways for a long time," said state railways minister Rajen Gohain, according to the Indian Express newspaper. "There must be a fault in the track as 14 bogeys have derailed, and this happened despite regular checking of the tracks."

While accidents are relatively common on India's sprawling rail network, the derailment of the Patna-Indore Express Train was among India's deadliest in at least five years.

A policeman stands at the site of one of India's deadliest train crashes in years. (Jitendra Prakash/Reuters)

It occurred near Kanpur city, a major railway junction and a key link in India's rail network for connecting the eastern and western parts of the country. Since the accident, some trains passing through Kanpur have been cancelled and others have been diverted to stations to the north and south.

India's vast railway system is the world's third largest, but lacks modern signalling and communication systems. Most accidents are blamed on poor maintenance, outdated equipment and human error.

According to a government report in 2012, about 15,000 people are killed every year in train accidents. The worst occurred in 1981, when a train fell into the Baghmati River in northern India, killing nearly 800 people.

Prime Minister Narendra Modi — who tweeted that he was "anguished beyond words" by Sunday's accident — pledged last year to invest $137 billion US over the next five years to modernize India's railway network, which is used by about 23 million passengers a day.