Brief History of Construction of Metro Railway Kolkata
The idea of underground railway in Kolkata was conceived by Dr. B.C. Roy, the then Chief Minister of West Bengal in the year 1949 to solve the problems of transport in the city. A survey was done by a team of French experts but nothing concrete came out. Kolkata had only 4.2% of the surface area as roads compared to 25% in Delhi and even more in other cities. To solve the transportation problem of Kolkatans, the Metropolitan Transport Project (Railways) was set up in 1969. The MTP had prepared a Master Plan in 1971 envisaging construction of five rapid transit lines for the city of Kolkata over 97.5 Kms. route length. Of these, the highest priority was given to the busy North South axis between Dum Dum and Tollygunge over a length of 16.45 Kms. and the work on this project was sanctioned on 01.06.1972
The section from Dum Dum to Tollygunge has been opened to passenger traffic starting from October 24, 1984 and finished on September 27, 1995.
Extension of Metro Railway from Tollygunge to Kavi Subhash was sanctioned in the year 1999-2000 and in this stretch has been commission in Phases and completed in 2010.
The Construction Method, New Technologies and challenges:
There was little know how in the country regarding construction of underground Metro Railway system. However, the challenge was met with and the work of Metro was completed.
Two methods – Cut and Cover and Driven shield Tunnelling – have been adopted for the construction of Kolkata Metro. The first method was used in the construction of major portion of the alignment and the second method had been adopted for construction of about one km long tunnels on either side of Chitpur Railway Yard upto Belgachia and Shyambazar Five-Point Crossing. The Cut and Cover methodology needs diversion of most of the surface traffic to other parallel roads. This was done for the construction of southern section from Esplanade to Tollygunge. But the same was not feasible in the Northern section from Esplanade to Shyambazar on Chittaranjan Avenue due to lack of sufficiently wide parallel roads. A modified Cut and Cover method had, therefore, been devised for this stretch. This method permits flow of traffic on the surface with the provision of deckings while the construction work goes on underneath.
New Technologies Used:
Metro construction is of a very complex nature requiring application of several new technologies in the fields of civil, electrical, signalling and telecommunication engineering. Indian engineers, backed by their own experience and supplemented by their studies abroad, adopted advanced technologies in the following fields for the first time in India.
·Cut and Cover method of construction using diaphragm walls and sheet piles.
·Use of extensive decking to keep the traffic flowing over the cut while construction is in progress underneath.
·Shield tunnelling using compressed air and airlocks.
·Ballastless track using elastic fastenings, rubber pads, epoxy mortar and nylon inserts.
Following Metro Projects are in various stages of completion in Kolkata area.
(i)Naopara-Airport-Barasat (18.13 Km)
(iii)Joka-BBD Bag-Diamond Park(16.75 km)
(iv)New Garia-Dum Dum Airport(32.00 Km)
(v)E-W Corridor(16.55 Km)