The Central Railway (CR) will conduct a 27-hour mega block from Saturday night to dismantle the British-era Carnac Bridge between Chhatrapati Shivaji Maharaj Terminus (CSMT) and Masjid Bunder station in south Mumbai.

The mega block will start at 11 pm (on November 19) and end at 2 am on November 21, due to which the schedule of suburban and express trains will get affected during this period, a release by the CR said.

The special block is likely to affect more than 37 lakh daily local train commuters as well as those traveling by outstation trains. More than 1,800 local train services operate on the Central Railway’s Mumbai suburban network comprising 'Harbour' and 'Main' lines that originate from CSMT in south Mumbai.

The bridge was built in 1866-67 and was declared unsafe by an expert team of the Indian Institute of Technology Bombay (IITB) in 2018, though the movement of heavy vehicles on it was stopped in 2014 itself, railway officials said.

In the release, the CR said, "The block will be operated to dismantle Carnac bridge which was declared unsafe for road traffic in the month of September this year." The officials said that a major portion of the iron bridge has already been demolished. Hence, during the block only the iron structure of the railway over bridge (ROB) will be cut and removed with the help of road cranes.

CR general manager Anil Kumar Lahoti, divisional railway manager Rajnish Kumar Goyal and other senior officials inspected the demolition work on Friday and gave necessary instructions.

"The heritage bridge has some six stones with inscriptions that mention the year of construction. These will be preserved suitably either at heritage gully or museum area," CR's chief public relations officer Shivaji Sutar said.

On the Main line of the CR route (CSMT to Kasara/Khopoli), the block will be operated between CSMT and Byculla stations for 17 hours. It means no train will run between the CSMT and Byculla station till 4 pm on November 20 from 11 pm on Saturday, the release said.

On the Harbour line (CSMT-Goregaon/ Panvel), the block will be operated between CSMT and Vadala stations for 21 hours. No train will run between CSMT and Vadala stations till 8 pm on November 20 from 11 pm on Saturday, it said.

The Mail-Express Yard lines will be made available after 27 hours, meaning 2 am on November 21, the release added.

During the block period, suburban trains will be operated from Byculla, Parel, Dadar, Kurla stations towards Thane, Kalyan, Kasara , Karjat side and vice versa, whereas on the Harbour line the services will be run between Vadala and Panvel-Goregaon stations, it said.

"As we have limited platforms for reversal of trains at Byculla, Parel, Dadar, Kurla and Vadala Stations, we will be running trains at less frequency," the CR said in the release and requested passengers to avoid unnecessary crowding at the suburban stations.

The CR said it has requested the civic transport bodies to run extra buses for the convenience of commuters during the block period and they have agreed to do so.

To avoid traffic congestion, 18 pairs of Mail-Express trains have been cancelled and 68 mail/express trains have been either short-terminated or short-originated at Dadar, Panvel Pune and Nashik stations, the release stated.

During the intervening night of Saturday and Sunday as well as Sunday and Monday, the CR will also operate a special traffic and power block for ROB girders launching at Kopri between Mulund and Thane for more than two hours each, the release said.

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