The Second Tunnel Boring Machine of AFCONS - Transtonnelstroy JV has started boring under riverbed Yesterday at 7.30 pm , on 24th May 2017 .
TBM S640 , nicknamed Prerna is now the second TBM to bore one of the two of India's first Underwater Railway Tunnel . The TBM was commissioned from Howrah Shaft on 22nd of April 2017 and reached Riverbed within Ten Days . Then the TBM was kept switched on and waited until Rachna reached Kolkata's riverbank . They wanted to pass the TBMs one by one under river as any techincal problems of TBMs under riverbed would have caused many problems , pausing both of them under river , which is dangerous . TBMs couldn't be easily taken out by just excavating the earth under river ! REMEMBER ---- YOU WERE UNDER RIVER !
The Tunnel Boring machine will need a minimum time of 30 to 40 days to reach Kolkata . For the first 2 to 3 days , it will bore at a speed of 5 metres per day . Then it will continue to bore the tunnel at a speed of 12 to 15 metres per day until it reaches Kolkata . Then the speed will be reduced to 5 metres per day following the suggestion of Kolkata High Court . This will take longer time to reach the Evacuation shaft , allotting more time to the Archeological Survey of India to give final clearance and allowing to amend the National Monuments Act to allow construction of Mahakaran Metro Station within 100 metres of 3 Heritage Buildings .
The TBMs will pass below the Kolkata Riverfront , with a Maximum Depth of 33.24 metres or 109 ft approx , that is equal to the height of a Ten-Storie Building !
After the Evacuation Shaft , the TBMs will climb upto a depth of 23 metres to reach Mahakaran Station , where the TBMs will be taken out , overhauled and again pushed towards Esplanade , which is their Ultimate Destination ! Then the TBMs will be re-nicknamed , and will be sent to some other cities to bore some other tunnels of other metrorails . Rachna and Prerna won't be together anymore !
The Tunnel Boring machine will need a minimum time of 30 to 40 days to reach Kolkata . For the first 2 to 3 days , it will bore at a speed of 5 metres per day . Then it will continue to bore the tunnel at a speed of 12 to 15 metres per day until it reaches Kolkata . Then the speed will be reduced to 5 metres per day following the suggestion of Kolkata High Court . This will take longer time to reach the Evacuation shaft , allotting more time to the Archeological Survey of India to give final clearance and allowing to amend the National Monuments Act to allow construction of Mahakaran Metro Station within 100 metres of 3 Heritage Buildings .
The TBMs will pass below the Kolkata Riverfront , with a Maximum Depth of 33.24 metres or 109 ft approx , that is equal to the height of a Ten-Storie Building !
For more updates of Kolkata Metro , check out Kolkata Metro Section . Have a Nice Day! Bye Bye !
I hope by the time the 2 TBMs finish the two sisters ( Rachna and Prerna ) would have done a commendable job
ReplyDelete15 days pass but no more updates..Pls update some..
ReplyDeletePls update garia to airport metro..
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