Green Line (Chennai Metro)

The Green Line is one of the two operational lines of Chennai Metro apart from the Blue line. The line stretches from to, covering a distance of 22 km. The line consists of 17 stations out of which nine stations are underground and the rest are elevated or on ground level.

Planning for the metro started in 2007-08 with the construction commencing in February 2009. Testing began in 2014, and the Commissioner of Metro Rail Safety approved the operations in January 2015. On 29 June 2015, commercial operations started between Alandur and Koyambedu stations on the green line with the first underground section between Thirumangalam to Nehru Park operational on 14 May 2017, which was later extended to Chennai Central on 25 May 2018.

Planning and construction
In 2006, a modern metro rail system was planned for Chennai modeled after the Delhi Metro. Delhi Metro Rail Corporation (DMRC) was tasked with preparing a detailed project report on the implementation of metro system in Chennai. Based on the report, the Government of Tamil Nadu approved the first phase of the project in November 2007. The first phase was planned with two lines covering 45.1 km with 25 km being underground. The first corridor would connect Washermanpet with Chennai International Airport extending for 23.1 km with 14.3 km being underground. In December 2007, Chennai Metro Rail Limited (CMRL) was incorporated and the Government of India gave approval for the project in January 2009.

In February 2009, a inr 1990000000 contract was awarded for the construction of a 4.5 km long viaduct along the Inner Ring Road between Koyambedu and Ashok Nagar. The construction started on 10 June 2009. In August 2010, the contract for supplying rolling stock was awarded to Alstom. In January 2011, a joint venture between Larsen and Toubro and Alstom was awarded the contract for design and construction of track works and a depot at Koyambedu for inr 4492200000.

On 14 February 2014, the maiden trial run was conducted between Koyambedu and Ashok Nagar stations. In August 2014, the metro received the statutory speed certification clearance from the Research Design and Standards Organisation. In January 2015, a report was submitted to the Commissioner of Metro Rail Safety for approval. In April 2015, the Commissioner of Metro Rail Safety inspected the rolling stock and submitted the report to the Railway Board.

On 29 June 2015, commercial operations started between Alandur and Koyambedu stations on the green line. On 14 May 2017, operations commenced in the first underground line between Thirumangalam to Nehru Park on the green line, which was extended to Chennai central on 25 May 2018.

Infrastructure
The trains are operated on double-tracked lines. The average speed of operation is 85 km/h and maximum speed is 120 km/h. Alstom supplies the rolling stock for the trains operated on the line. The trains are air-conditioned with electrically operated automatic sliding doors and have a first-class compartment with a dedicated section reserved for women. The trains operate on 25 kV AC traction catenary system. The trains are connected to the grid via overhead electric cables and are equipped with regenerative braking with a capacity to recover 30–35% of the energy during braking. The electricity is supplied by Tamil Nadu Electricity Board.

Network


A total of 26 stations are operational along the blue line with 13 underground stations. In the underground sections, a walkway runs along the length with cross passages every 250 m for the maintenance and emergency evacuation. The underground stations have an average width of 200 m and average depth of 20 ft from the ground level. The length of the stations in Phase 1 extension is 180 m. The elevated stations have three levels with the concourse level at a minimum height of 5.5 m above the ground level and platform level above the concourse while the underground stations have two levels with platform screen doors. The stations are air-conditioned and are equipped to be disabled and elderly friendly, with automatic fare collection system, announcement system, electronic display boards, escalators and lifts. Paid parking facilities are available for two wheelers in most stations and four wheelers in select stations.

The line connects the central and the southwest ends of the city. The stations include: under construction

Operations
, the metro operates trains from 5 AM to 11 PM with an average frequency of one train every 12 minutes in peak hours and every 18 minutes in lean hours in the green line. The main operational control center (OCC) is located in Koyambedu where the movement of trains and real-time CCTV footage obtained is monitored. Chennai Metro maintains a major depot at Koyambedu covering an area of 26 ha which houses maintenance workshops, stabling lines, test tracks and a washing plant for the trains. The minimum fare is ₹10 and the maximum fare is ₹50. There are six types of tickets issued by CMRL for travel in Chennai Metro.