The new Tallah bridge will be built by L&T in 21 months, a senior PWD official said.

The new bridge will stand close to the old structure, which is being demolished. Construction work will begin in mid-April.

The cost of building the new bridge has been pegged at Rs 300 crore, the official said.

“The new bridge will be a bowstring girder structure with far greater load-bearing capacity than the existing one,” the official said. “The commissioner of railway safety gave his clearance for the new structure two weeks ago. There are no more hurdles in the construction of the bridge.”

The bridge that connected large parts of north Calcutta with Shyambazar had been commissioned in 1962. The underbelly of the bridge was supported by strands of steel ducts, many of which had snapped.

Based on reports submitted by engineers and experts, the government decided to pull down the structure to make way for a new one.

The proposed bridge will have a 24m wide deck — 5.5m more than the existing one. The existing pillars will have to be pulled down and new ones built to bear the load of wider decks, a PWD engineer said. Once commissioned, the new Tallah bridge will have a carrying capacity of over 350 tonnes, 100 tonnes more than the old structure.

“The new bridge will be a four-lane structure, unlike the old ones which had space for three lanes split into four. The design specifications of the proposed structure have been routed through the Kanpur-based Research Designs and Standard Organisation to avoid conflict with the railways,” the PWD official said.

Unlike Majerhat, the state government has decided to take the railways into confidence while finalising the design and structure of the new Tallah bridge.

The Research Designs & Standards Organisation (RDSO), under the ministry of railways, has a bank of standard designs for rail overbridges.

With the new design for the Tallah bridge clearing all the specifications of the RDSO, the clearance from the commissioner of railway safety didn’t take much time.

A nod from the commissioner of railway safety is mandatory for all bridges built over railway tracks. The final clearance for the Majerhat bridge is to reach Nabanna.

Soil test for the proposed structure has already been carried out. Jaw crushers and diamond cutters have been pressed into action to pull down the remaining part of the concrete bridge as early as possible.

“We hope to finish the demolition work by April 15. The site would then be handed over to engineers from L&T,” the official said.