Dismantling of the Tallah bridge will start after the railways cleared the decks, mayor Firhad Hakim said on Saturday when PWD engineers got together to discuss if certain changes could be made to the proposed design of the new bridge.

The railways has objected to the PWD’s steel-arch bowstring design citing technical problems about how multiple piers could come in the way of movements of trains on the tracks below. It has proposed a cable-stayed structure because that will require two spans supported by a single pier.

Sources at Nabanna said senior engineers of the PWD had decided to review the drawing that was earlier submitted to the railways so that both agencies could agree on a common design that would be the best alternative to the existing 57-year-old structure.

On January 2, Bengal chief secretary Rajiva Sinha met representatives of both the agencies and later constituted a task force comprising engineers from the railway and PWD to work together on the design of the proposed bridge. Sources said once the design of the bridge was formalised, it would be sent to the Research Designs and Standards Organisation (RDSO) in Lucknow for clearance. The dismantling of the existing structure will begin only after the clearance reached Nabanna, senior officers of the PWD said.

“Dismantling of the existing structure will only add to the woes of commuters since a considerable number of small vehicles, including cars, were still using the bridge. It is no point pulling down the existing structure and then mulling over the proposed design of the alternative bridge,” said a senior officer of the PWD.

Tallah bridge is a crucial link for lakhs who commute from large parts of north Calcutta, including Dunlop, Baranagar, Sinthee and Chiria More, to central Calcutta every day. Lalbazar has been struggling to put in place a traffic diversion plan for buses, mini-buses, heavy vehicles and others travelling to and from central Calcutta to deep north and vice-versa.

The dismantling of the existing bridge was scheduled to start from the night of January 4 but that has been now postponed. Sources said, next week engineers from the PWD and railways would meet to firm up the alternative design. Once the design is finalised, Sinha will meet task force members to understand the features before sending it to the RDSO.