Line 4A (Mumbai Metro)

The Green Line is part of Mumbai Metro rail network for the city of Mumbai, Maharashtra, India. During the construction the line was divided into 3 smaller lines - Line 4 ( to ), Line 4A ( to ), and Line 10( to ). The line also has a proposed spur line called Line 11 from to SPM Circle. The line proposed to be of length 60.409km of which 35.2km is under construction. The line connects the regions of Mira Bhayandar to Wadala via Gaimukh and Kasarvadavali. Construction of Line 4 started in October 2018 while the construction of Line 4A started in September 2019. Meanwhile, the proposed Line 10 is currently under environmental review while Line 11 is undergoing Soil testing. The line has a total of elevated 38 stations of which 34 are under construction. The main line is fully elevated and has zero underground stations. In addition, the proposed spur line (Line 11) has 16 stations of which 2 are elevated and the remaining 14 are proposed to be underground.

The line offers interchange with the under construction Orange Line at , Pink Line at , and the Yellow Line at . In addition the line has a proposed interchange with the Red Line at and Aqua Line at Chhatrapati Shivaji Maharaj Terminus.

Planning

Line 4

In June 2015, the Mumbai Metropolitan Region Development Authority (MMRDA) proposed building a Wadala-Thane-Kasarvadavali metro line as part of a plan to build six new metro lines at a total estimated cost of . Line 4 was approved in June 2016, and was estimated to cost .

The foundation stone for Metro 4 was laid by Prime Minister Narendra Modi on 24 December 2016. The Maharashtra Coastal Zone Management Authority granted Coastal Regulation Zone (CRZ) clearance to the project in February 2017. Over of the line passes over water bodies in Bhakti Park and Wadala, both areas classified as CRZ II, where regulations limit construction activities. A total of 48 piers are proposed to be built in the CRZ II zone. The MMRDA proposed building metro car depots for the line on a plot at Owala village in Thane district and another in Vikhroli. The agency stated that the line would require two depots due to its length.

The MMRDA used a drone to carry out survey work for Metro 4. The drones were fitted with 360 degrees camera that provide up to accuracy. The aerial survey takes less time than a regular survey, achieves greater accuracy and helps protect against false claims for compensation.

The MMRDA appointed Systra MVA Consulting India Pvt. Ltd. as the detail design consultants for Line 4 on 9 November 2017. A consortium of DB Engineering, Louis Berger and Hill International was awarded a project management and construction management services contract for the Metro 4 project in April 2018. In October 2018, the MMRDA announced that it would construct Metro 4 along with three flyovers to minimize traffic disruption, with the metro running on the upper deck of the flyover. The three flyovers will be built at Bhayander Pada, Kasarvadavli and Anandnagar near Ghodbunder.

In May 2019, MMRDA Metropolitan Commissioner R.A. Rajeev announced a modified plan to use Siddharth Colony as the interchange station with Line 2. The original plan had proposed to use the Eastern Express Highway station on Line 2B and Siddharth Colony on Line 4 as the interchange stations. However, the two stations are approximately away from Siddharth Colony and the change was made to simplify passenger transfers.

Line 4A

In February 2017, the MMRDA said it was studying the feasibility of extending the corridor from Kasarvadavali to Gaimukh. In March 2017, the agency said that it was conducting a pre-feasbility study on extending the line from Wadala to Mumbai General Post Office in South Mumbai, via the Mumbai Port Trust. The proposed extension is estimated to cost 300 crore per kilometer. The extension from Kasarvadavli to Gaimukh was approved by Fadnavis at the 144th meeting of the MMRDA on 12 January 2018. The extension is estimated to cost .

Line 10

In June 2015, the MMRDA announced Metro Master Plan covering over 300 km of metro lines to decongest roads and reduce pressure on the suburban railway system. As part of the master plan it announced a brand new line named Line 10, which would serve as an of the announced Line 4. The line would start in and terminate in where it would intersect with the Red Line. The line is proposed to add 4 brand new stations, all of which are proposed to be elevated despite the line having some underground sections.MMRDA later stated that the Line 4, 4A, and Line 10 would form the Green Line. In December 2022 MMRDA appointed SYSTRA MVA Consulting – DB Engineering & Consulting JV as the General Consultant responsible for the execution of the line. The line is currently awaiting environmental clearance for construction as it passes through the Sanjay Gandhi National Park.

Line 11

Initially the Line 11 was announced as an extension from the Line 4 to the Chhatrapati Shivaji Maharaj Terminus. The line initially proposed having 2 elevated stations and 8 underground sections running from Wadala to the CSMT. The Maharashtra government assigned the MMRDA to execute this project. However, in early the project was transferred from the MMRDA to the MMRCL. This change in agency saw the line being reworked completely. MMRCL announced the line had a new alignment taking a more central route south of Byculla. The rework saw the line being converted to that of a spur line rather than a natural extension of the Green Line. It also saw the addition of new stations and the extension of the line beyond CSMT. The line construction estimates were also doubled from Rs.8,739 crore to Rs.16,000 crore.

In May 2025 as part of the Dharavi redevelopment project it was proposed extending the spur Line 11 from Anik Nagar Bus Depot to Dharavi via Sion. This proposal was part of the Dharavi redevelopment project, which included the efforts to make Dharavi a transportation hub in Mumbai.

Depot

The MMRDA considered plots in Wadala, Aarey Colony and Gaimukh Nagar in Thane to build a depot for the line. On 16 October 2023, the state urban development allotted a plot of land at Mogharpada in Thane to the MMRDA at no cost. Nine hectares of the plot is reserved for use by the BMC for the Coastal Road and a further is protected mangrove land. The MMRDA will utilize a portion of the remaining plot to build a depot that serves Lines 4, 10 and 11. The land left over after building the depot is zoned for residential and commercial use. For Line 11 however, MMRC proposed a depot besides Anik Nagar Bus Depot station instead of using the Mogharpada depot.

Construction

Tendering

Line 4 & Line 4A

The MMRDA invited bids for civil work on the corridor on 4 January 2017. The tenders for construction of viaducts and stations were divided into five packages - Wadala to Amar Mahal Junction, Garodia Nagar to Surya Nagar, Gandhi Nagar to Sonapur, Mulund Fire Station to Majiwada and Kapurbawdi to Kasarvadavali. Metro 4 was tendered alongside Metro 2B. L&T, Afcons Infrastructure, Tata, NCC and JMC, Reliance Infrastructure-RdE, JKumar Group, ITD Cementation, CHEC-TPL bid for packages on both Metro 2B and Metro 4. A total of 10 firms and/or consortia submitted bids for the two lines, two of whom (Simplex Infrastructure and a consortium of GHEC-RCC-JV-China) bid exclusively for Metro 2B packages.

The construction work was awarded through the engineering, procurement and construction (EPC) model in April 2018. A joint venture between Reliance Infrastructure and Italian firm Astaldi S.p.A. was awarded three packages between Kasarwadavali and Wadala worth . The contract for the remaining two packages, worth a combined , was awarded to a joint venture between Tata Projects Limited and China Harbour Engineering Company. The civil work was expected to be completed in 30 months. Construction began in October 2018. About 80% of soil-investigation works and 66% of utility works had been completed by 3 June 2019.

In September 2019, the MMRDA awarded a contract to J Kumar Infraprojects to build the viaduct and two stations for the Metro 4A extension from Kasarvadavli to Gaimukh. In August 2020, the Bombay High Court granted the MMRDA permission to carry out construction in a mangrove buffer zone. Survey work on the land for a depot at Mogharpada began in January 2022.

The MMRDA stated that 37% of total work on Lines 4 and 4A had been completed by June 2022. The agency stated that 43.44% of viaducts and 25.20% of work on stations on Line 4 had been completed. On Line 4A, 39.03% of viaducts and 19.82% of work on stations was completed. By November 2022, 41% of civil works on Line 4 and 45% of work on Line 4A had been completed.

The Bombay High Court dismissed two petitions filed by Indo Nippon Chemical Co. Ltd. and Shree Yashwant Co-operative Housing Society Ltd. challenging the alignment for Line 4 in March 2023. In September 2023, the MMRDA awarded a contract to a joint venture between SEW Infrastructure and Vishwa Samudra Engineering to build the depot at Mogharpada. It also awarded a to Apurvakriti Infrastructure Pvt Ltd. lay ballastless railway tracks connecting Mulund Fire Station with Gaimukh and the depot.

Stations

32 stations are being planned on Line 4. Most of them were either in the stage of planning or under early stages of construction (as of November 2018)

2 stations are being planned on Line 4A. Connected to word Gaimukh to Kasarvadavali also connect Metro 10.

Main Line

Branch Line

Cost

Line 4 is estimated to cost , and Line 4A is estimated to cost . The Maharashtra Government signed an €545 million (₹4,000 crore) loan agreement with German development bank KfW to fund construction of Metro 4 and 4A in November 2020.

Infrastructure

Rolling stock

The MMRDA awarded a contract to Alstom to supply 234 metro coaches for Line 4 and 4A in March 2021. This was Alstom's first order after acquiring Bombardier Transportation in January 2021. However, the company initially cancelled the order in March 2022, citing delays in completing the project. In February 2025, Larsen & Toubro (L&T), in collaboration with Alstom, has been awarded a significant contract to supply critical systems for the line. This contract encompasses the provision of 39 six-coach trains, Communication-Based Train Control (CBTC) signaling and train control systems, telecommunications, platform screen doors, and depot machinery and plant for the Mogharpada Depot.

Depot

The depot for the line is located at Mogharpada in Thane. It will also serve as the depot for Line 10 and Line 11. The depot has a maximum capacity for 64 stabling lines, half of which are reserved for future use, in addition to 10 inspection bays lines and 10 workshop lines. The depot also houses the operational control centre, administrative building, maintenance and workshop building, auxiliary substation, and staff quarters.

Pocket track

The Bhakti Park station will have a pocket track to enable trains to park off the main line. Line 4's depot at Mogharpada also serves Line 10 and Line 11 which creates the possibility of trains having to run without passengers from the depot to Chhatrapati Shivaji Terminus during morning hours. The pocket track enables trains to park off the main line without traveling to the last station on the line.

References

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Mumbai Metro lines