Mumbai, the financial capital of India, has unparalleled opportunities with the rapidly expanding metro network. Mumbai Metro Line 3 (Aqua Line) is a key upcoming project which will enhance transportation in the city. State-of-the-art technologies and the latest methodologies are being adopted for the construction of the project.
The project aims to provide a mass rapid transit system to supplement Mumbai’s inadequate suburban railway system by bringing the metro closer to its residents. Once operationalised, the city will witness a significant reduction in traffic volumes. Additionally, local transit facilities will get a boost.
Project overview
Mumbai Metro Rail Corporation Limited (MMRCL) is the nodal agency responsible for the implementation of the project. It was constituted as a joint venture (JV) of the Indian government and the Maharashtra government on a 50:50 sharing basis.
The Mumbai Metro Line 3 project, connecting the Colaba–Bandra–Santacruz Electronics Export Processing Zone (SEEPZ) with an extensive 33.5 km network, is almost complete. The line consists of 26 underground stations and one at-grade station. In March 2024, MMRCL commenced trial runs on the Aarey-Bandra Kurla Complex (BKC) stretch. During the trial runs, various systems, including signal telecommunication, rolling stock, tracks and traction, were validated.
Phase I of the project, covering approximately 12 km, will connect Aarey to BKC, and is expected to be commissioned by the end of September 2024. Meanwhile, Phase II (BKC to Cuffe Parade), spanning 22 km, will be commissioned in 2025. Although the civil construction contracts were awarded for both phases around the same time, commissioning will be done at different stages. Once fully complete, the project will facilitate commute from Colaba to SEEPZ within one hour, and will run in the north-south and south-north directions like the suburban networks of Central Railway and Western Railway.
Key civil contractors for the project include Shanghai Tunnel Engineering Company Limited, Larsen and Toubro Construction Limited, OJSC Mosmetrostroy, Hindustan Construction Company Limited, China Railway Tunnel Group and J. Kumar Infraprojects Limited. Meanwhile, notable consultants include the Delhi Metro Rail Corporation (DMRC) (master plan preparation), RITES Limited (retailed project report preparation), and DB International GmbH, Tata Consultancy Services and Transport East-West Team GmbH (preparation of feasibility study).
Advancements in segment specifications
Rolling stock
The consortium of Alstom Transport India Limited and Alstom Transport S.A. France was awarded the contract for the design, manufacture, supply, installation, testing and commissioning of rolling stock for the project in 2018.
Alstom has indigenously designed, manufactured and commissioned 31 lightweight, fully furnished modern passenger train sets of eight cars each. The company handed over the first train set for the project in August 2022.
These trains are based on the theme “Dynamic Fluidism” and prioritise high interior density layout to maximise space efficiency, enabling each train set to carry 3,000 passengers per trip. They feature a unique design and a wide range of configurations, ensuring optimal performance through a combination of proven, reliable components and innovations. As per calculations based on the ISO 22628 standard, these trains are 96 per cent recyclable and 99 per cent recoverable. Moreover, they are projected to reduce traffic by 35 per cent and lower air and noise pollution.
The Research Designs and Standards Organisation completed the trial runs of rolling stock for the Mumbai Metro Line 3 project in June 2024. These were conducted at a maximum speed of 95 km per hour with both empty and loaded rakes.
Once Phase I is completed, MMRCL will seek safety approval to commence driverless operations. A six-month trial is required to obtain clearance from the Commissioner of Metro Railway Safety for driverless operations.
Signalling and operations
These trains are also being equipped with Urbalis 400, the latest generation of communications-based train control signalling technology. The adoption of this technology will result in an increase in the average capacity by 30 per cent in manned services and unattended train operations. Meanwhile, DMRC will be responsible for the day-to-day operations of the metro line.
Fare collection
MMRCL will use an open-loop automated fare collection (AFC) system. With this, passengers will be able to make contactless post-paid and prepaid payments using smart cards, while also being able to pay for tickets via QR codes.
In 2019, the JV of Kalindee Rail Nirman (Engineers) Limited and Asis Elektronik ve Bilişim Sistemleri A.Ş. won the contract for the design, manufacture, supply, installation, testing and commissioning of the AFC system for the project.
Others
The building information model was undertaken by SYSTRA India to optimise the design, detect and resolve clashes early, and improve communication between the various stakeholders involved in the project. It has resulted in cost savings of over Rs 25 billion, along with improved quality of construction.
Financing details
The Mumbai Metro Line 3 project is being jointly funded by the Maharashtra government, the Mumbai Metropolitan Region Development Authority (MMRDA) and the Japan International Cooperation Agency (JICA). The state government approved funds worth Rs 11.63 billion for this project in June 2024. More recently, in July 2024, JICA extended the fifth and final tranche of an official development assistance loan amounting to JPY 84.26 billion (approximately Rs 44.74 billion). This is a priority project for both the Japanese government and JICA. The agreement for Tranche I of the project was signed in 2013, with an approved amount of JPY 71 billion. The agreement for Tranche II was signed in 2018, with an approved amount of JPY 100 billion. In 2019, the agreement for Tranche III was signed, with an approved amount of JPY 39.92 billion. Furthermore, the agreement for Tranche IV was signed earlier in 2024 and the approved amount was JPY 58.94 billion.
Cost overruns and construction challenges
The original cost of the project was Rs 231.36 billion and was initially scheduled for completion by December 2021. However, the project faced challenges due to the Covid-19 pandemic, geographic and demographic issues, and land acquisition difficulties, especially with approvals for the Aarey car shed land acquisition. As a result, the project incurred extra costs, including Rs 5.2 billion for consultant fees, Rs 7 billion for rehabilitation and resettlement, Rs 15 billion for architectural systems, Rs 1.5 billion for office expenses and Rs 10 billion for agreements. With these additional expenses, the total project cost escalated to Rs 372.76 billion.
Since the project is entirely underground, with station concourses at 10-14 metres below ground and platforms at depths of 18-20 metres below ground, mobile network and internet propagation poses significant challenges. To address this, MMRCL plans to deploy cellular coverage from mobile service providers including Airtel, Jio, Vodafone and MTNL. In October 2023, MMRCL awarded an in-building solutions contract to ACES India Private Limited for providing telecom infrastructure to ensure uninterrupted mobile and internet connectivity for passengers while commuting.
Excavation and tunnelling works hinder project execution. Many permutations and combinations of tunnelling methods have been used for the project. Initially, tunnelling was done using tunnelling boring machine (TBM) techniques. Subsequently, the tunnels were widened and a large cavity was created using the new Austrian tunnelling method. A total of 17 TBMs have been deployed for carrying out tunnelling works.
Future plans
This project aligns with the government’s priorities to enhance urban mobility and promote sustainable development in the Mumbai region. It aims to reduce traffic congestion, decrease air pollution and boost economic productivity by improving public transportation infrastructure. It will also contribute towards meeting the Sustainable Development Goals, especially Goals 11 and 13, which focus on sustainable cities and communities and climate action.
Going ahead, MMRDA is planning to introduce an automated rapid transit system, commonly referred to as pod taxis, in BKC, Mumbai, to improve connectivity. Sai Green Mobility Private Limited, in collaboration with technology partner M/s. Ultra PRT, is likely to implement this project, where MMRDA will provide the infrastructure, while the concessionaire will secure project funding.