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 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 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. -- PTI