One body was recovered from the debris of the collapsed Majerhat bridge in south Kolkata on Wednesday, taking the toll in the incident to two.
Chief Minister Mamata Banerjee, who visited the site after returning from Darjeeling, told reporters that two persons were missing and one body was recovered from the debris.
Police said the body recovered might be of one of the missing persons.
Operations to locate those who might still be trapped in the debris were stepped up. Police and National Disaster Response Force personnel continued their rescue work at the accident site with cranes, earthmovers and drilling machines.
"It may take another two days to cut through the concrete slabs. The people engaged in the work are trying hard to cut them," said Meeraj Khalid, DC South, Kolkata Police.
"It is God's grace that many people were not killed," Banerjee said, adding a committee headed by Chief Secretary Malay De will investigate the cause of the collapse.
One person, identified as Soumen Bag, was killed when a part of the 50-year-old bridge on the arterial Diamond Harbour Road caved in on Tuesday evening trapping several people and crushing many vehicles.
Banerjee said the police and administration have done well in carrying out the rescue work and an emergency meeting has been convened on Thursday to take stock of the situation.
She said papers of old bridges were not available.
"Still we are trying to conduct regular survey of those bridges with available technical experts," she said, adding work by Metro Railways in the area during the past nine years had caused vibration and resulted in many problems there.
The area near the site had been dug up for a Metro Rail project and construction material is strewn all over the place.
Opposition parties in the state have alleged that the Trinamool Congress government's 'callousness' towards the repair of old bridges was the main reason behind the collapse.
Banerjee sought cooperation of the people in the area and said that they might face hardships due to collapse of the bridge.
Those who did good work during the rescue operations would be rewarded, she added.
The bridge in Alipore area in south Kolkata runs over the Majerhat Railway Station and connects the city centre with the heavily populated Behala, vast areas of the southwest suburbs and neighbouring South 24 Parganas district.
With the Diamond Harbour Road being closed, thousands of commuters were stuck in jams.
A traffic police officer said vehicles that usually move to and from the city through Majerhat bridge have been diverted through various other roads.
Train movement below the Majerhat bridge was normal on Wednesday after being stopped as a precautionary measure on Tuesday, Eastern Railway spokesman R N Mahapatra said.
"Train services of Circular Railway from Dum Dum to Majerhat have resumed this morning," he said.
However, services in the Circular Railway portion of railway track between New Alipore and Majerhat stations that passes under the bridge are temporarily suspended, he added.
Eastern Railway had stopped movement of trains on the track on Tuesday as a precautionary measure.
Tram services have been completely suspended along CGR Road-DH Road and Judges Court Road, a Kolkata Traffic Police source said.
The Kolkata Disaster Management Department, the NDRF and the state fire department conducted search operations through the night, officials said.
The rescuers tried drilling the concrete slabs, used sophisticated cameras and engaged sniffer dogs to ensure anybody trapped under the rubble could be reached and rescued. Intermittent rains complicated the operation.
Additional lighting arrangements were made to aid rescue work at night, the officials said.
A team of senior officials of CESC, responsible for power supply in the city, visited the site last night to ensure adequate power supply in the area.
A mini bus, four cars and a few motorcycles that were damaged in the bridge collapse were removed using cranes, the official said.
Bharatiya Janata Party MP Roopa Ganguly, who visited the site Wednesday morning, held the TMC-led state government responsible for the collapse and alleged that the bridge was not maintained properly.
The police lodged a suo motu case against unknown persons in connection with their involvement in the mishap, a police officer said.
This is a third bridge collapse in the city since 2013.
The railways had alerted the Kolkata Metropolitan Development Authority (KMDA) about weak support beams, exposed reinforcements and even cracks on piers of the 50-year-old bridge.
The road bridge runs over the Majherhat Railway Station on the Sealdah-Budge Budge line.
In the letter to KMDA, dated July 27, the Eastern Railway Zone's Deputy Chief Engineer had highlighted the need for inspection of sections of the bridge, flagging several concerns regarding its structural efficacy.
A copy of the letter was marked to the railway Senior Deputy Engineer, Sealdah.
KMDA is the statutory planning and development authority for Kolkata metropolitan area and state Urban Development Minister Firhad Hakim is the chairman of its board.
'The condition of RCC beams of the bridge which supports utility services, are not in good condition and it requires suitable replacement in a programmed manner at the earliest,' the letter to the Superintending Engineer, South Circle, KMDA said.
A copy of the letter is with PTI. Sources in the railway ministry said soon after the collapse of the Gokhale Bridge in Mumbai in July, an inspection of a section of the Majerhat Bridge above the Sealdah-Budge Budge line was conducted which revealed these deficiencies.
The letter urged the KMDA to make preparations at their end so that railway could initiate maintenance work.
It also raised concerns over a nearby span of the bridge towards Mominpur, which they found to be 'visibly deflected'.
'This needs to be a complete inspection from your side and necessary action thereof,' wrote the Eastern Railway Zone's Deputy Chief Engineer.
Further, the bridge engineer listed out the anomalies detected in the road over bridge -- weak RCC and steel beams which needed replacement, locations with exposed reinforcements, and some cracks in piers over isolated locations.
After the collapse of the Vivekanada flyover in the city in March 2016, the state government had mandated Rail India Technical and Economic Service (RiTES) to survey the conditions of different bridges in Kolkata.
The under-construction flyover came crashing down in crowded Burrabazar area, the wholesale business hub of the city, on March 31, 2016 claiming 26 lives.
After the tragedy, the KMDA and the state PWD had entrusted a team of consulting engineers with the task of auditing flyovers and rail overbridges in the city.