Metro Projects: Types, Advantages & Challenges of metro construction in India
- Cemtech Infra Solution Pvt. Ltd.
- Jun 15, 2022
- 6 min read
Index
The Indian metro rail system is growing at a rapid pace and is undoubtedly a boon to commuters (because they are clean, fast, comfortable and cheap!) in big and medium cities.
They are equally contributing to making developing cities more comfortable, and sustainable. It is capable of changing the way people commute within cities in India.
Let us dive into how India is constructing its network of metros across Indian cities.
Metro Rail Projects under implementation across India
It takes a monumental effort to build such a complex transit system in a densely populated country like India. But, thanks to technology and capable engineers, India's Metro Rail network is rapidly expanding in major cities. About 15 cities have already been reached, and new metro rail systems are currently being built in 20+ Indian cities, bringing about a radical shift at a breakneck speed.
The following table gives information on cities that will cover metro networks in the coming years.
Under construction metro projects in India | Proposed metro projects in India | Approved metro projects in India |
Agra Metro, Uttar Pradesh | Aurangabad Metrolite, Maharashtra | Gorakhpur Metrolite Uttar Pradesh |
Ahmedabad Metro, Gujarat | Bangalore Metrolite, Karnataka | Kozhikode Metrolite, Kerala |
Bangalore Metro, Karnataka | Bhavnagar Metrolite / Metro Neo, Gujarat | Nashik Metro Neo, Maharashtra |
Bhopal Metro, Madhya Pradesh | Chennai Metrolite, Tamil Nadu | Trivandrum Metro, Kerala |
Chennai Metro, Tamil Nadu | Coimbatore Metro, Tamil Nadu | |
Delhi Metro, Delhi-NCR | Delhi Metrolite, Delhi | |
Gurgaon Rapid Metro, Haryana | Guwahati Metro, Assam | |
Hyderabad Metro, Telangana | Jamnagar Metrolite / MetroNeo, Gujarat | |
Indore Metro, Madhya Pradesh | Jammu Metro, J&K UT | |
Jaipur Metro, Rajasthan | Prayagraj Metro, Uttar Pradesh | |
Kanpur Metro, Uttar Pradesh | Raipur Metro, Chhattisgarh | |
Kochi Metro, Kerala | Rajkot Metrolite / Metro Neo, Gujarat | |
Kolkata Metro, West Bengal | Srinagar Metro, J&K UT | |
Lucknow Metro, Uttar Pradesh | Uttarakhand Metro, Uttarakhand | |
Meerut Metro, Uttar Pradesh | Vadodara Metrolite / Metro Neo, Gujarat | |
Mumbai Metro, Maharashtra | Varanasi Metro, Uttar Pradesh | |
Nagpur Metro, Maharashtra | Vijayawada Metro, Andhra Pradesh | |
Navi Mumbai Metro, Maharashtra | Visakhapatnam Metro, Andhra Pradesh | |
Noida Metro, Uttar Pradesh | Warangal Metro Neo, Telangana | |
Patna Metro, Bihar | | |
Pune Metro, Maharashtra | | |
Surat Metro, Gujarat | | |
Types of metro structures
There are two types of structures in metro construction:
Elevated metro
Underground metro
Let's have a better understanding of the civil works involved in an elevated and underground metro system!
Elevated Metro construction
Precast segments are used in the majority of the viaduct structures, which are built using the underslung girder method. This method has the advantage of allowing the viaduct deck spans to be erected quickly on-site with minimal interference to traffic below.
Viaducts are multi-span bridges that cross over roadways, rivers, and valleys. Viaducts on the Gautrain project typically span 40 to 50 meters between piers. The construction of viaduct decks has been proceeding for several months at various points along the route. Three girders are being employed simultaneously, and together they will create a viaduct deck structure of approximately 10.5 kilometres.
Underground Metro construction
The underground station construction employs the cut and cover engineering technique. To retain existing utility lines and build soldier piles or any other earth retaining structures, this approach usually starts by excavating the ground surface to a sufficient depth. The surface opening is then covered with a temporary street decking, which allows traffic and pedestrian movement to continue above the decking while excavation takes place beneath it.
Cut and Cover method
The cut-and-cover method is ideal for building a junction box and a cut-and-cover tunnel method in the soft or mixed ground, especially for shorter excavations (less than 30m). • Top-Down and Bottom-Up are the two basic cut and cover construction techniques. Station boxes can be built using either approach, although tunnel boxes are typically built from the bottom up. Retaining walls and a strutting system make up the majority of the system.
Underground Metro Vs Elevated Metro
Elevated Metro
The vertical gradient (maximum of 3.5%) and horizontal radius of the railway alignment is limited (about 150m).
Because it is extremely difficult to get land beyond the road's ROW (right of way), the elevated metro will follow existing roads.
The land is valuable, if not uncommon, and the acquisition or removal of structures can cause a project to stagnate.
Existing barriers such as road crossings, road flyovers, railway bridges, and even another elevated metro are all navigated by the elevated routing.
Sharper turns mean greater noise, more train maintenance, and possibly jeopardized safety standards.
As a result, the city road network governs elevated alignment development, and the shortest and best alignment designs are frequently compromised, increasing capital and operational costs.
Underground metro
Unlike the elevated metro alignment, the UG metro's railway alignment has no such constraints and may be planned for optimal performance.
Horizontal curves and vertical gradients can be improved; the distance between two places can be reduced since the line does not have to follow the road above.
The land needs are reduced because only entry/exit, auxiliary buildings, and certain service shafts are visible above ground.
During construction, there are apparent engineering obstacles such as building safety inside the tunnel effect zones and station area, traversing under a water body, navigating the deep foundations, and unpredictable geology.
Which one is better for India - The elevated or Underground metro system?
Although underground metro rail is a better idea, it is not a feasible solution in India. There are cable connections, sewage lines, and building foundations underground that are difficult to navigate, and the curves can only be as tight as the underground architecture allows.
Expansion, such as adding a new line, making platforms longer, or any other construction, is extremely difficult once built. In India, all metro developments are new, necessitating the use of a boring machine, but in industrialised countries, most constructions use the 'cut and cover' methodology.
It necessitates: Excavating the area, Building the tunnel, and Covering it again.
This would have been feasible back in 50-100 years when there was less inhabitation and it would have cost very less compared to the elevated subways. However, that is not the case today. In a densely populated country like India, constructing underground metros is a huge challenge. It will entail land acquisition, a longer timeframe for project completion and resettlement of people living in the surrounding. Therefore, elevated metro rail is better for India!
Challenges in Metro Construction
Even though metro trains are a necessity, they come with their own set of problems. Financial viability, wrong traffic estimation, land acquisition and resettlement concerns, and noise pollution, are a few to mention.
Financial viability
The precision of passenger estimation and traffic demand forecast depicts the financial viability of any metro rail project. The more accurate these estimates are, the more easily the technical justifications can be made for the project. Moreover, a ridership forecast acts as a guide for evaluating the socio-economic impacts. But, if the ridership estimation goes wrong, it can cost the infrastructure resources causing a huge fund void. Jaipur Metro is one such example. Therefore, financial viability needs to be taken care of for a successful project outcome.
Land Acquisition and resettlement issues
Land acquisition has always been a core part of any mega infrastructure project. Tier 1 and tier 2 cities in India are densely inhabited, which creates a lack of space available for metro rail projects. Land acquisition is a pre-construction process that requires surveys to identify the people and properties that will be affected due to metro construction. In such cases, resettlement becomes an option but extends the project timeline due to its own challenges. Thus we can say that land acquisition is inevitable, but with proper measures like suitable rail route alignment and using advanced engineering techniques, it can be minimised.
Traffic Congestion issues
The majority of metro rail lines, particularly elevated tracks, are being built alongside or within the existing right-of-way. As a result, traffic must be temporarily diverted. This diversion of traffic away from current highway channels increases traffic loads on nearby roads, causing congestion and traffic jams.
Noise Pollution and Vibration Issues
Industrial machinery and building equipment can produce vibrations and raise ambient noise levels during the construction process. Vibrations created during the construction phase can negatively affect the surrounding buildings leading to structural cracks in them. Also, not to forget the noise involved in such mega project construction. It can have adverse effects on people’s health living in the vicinity, let alone the infants and elderly ones.
Why the Jaipur Metro is considered a failed project
Leading to a decline in ridership, the Jaipur Metro Railway Corporation (JMRC), which is considered a "failed" project, is struggling to fulfil operational costs every year.
The first section of the Jaipur Metro, which opened in June 2015, performed poorly, with an average ridership of only 19.17 per cent of expected ridership in the first 22 months. According to the CAG report, JMRC's operational revenue of Rs 18.87 crore was insufficient to cover its operating expenses of Rs 85.56 crore for the first 22 months.
The JMRC study was done after the Jaipur Metro had been operational for a year in order to improve services and increase usability. 464 people took part in an online survey over the course of three weeks, submitting their ideas and views.
According to 53% of participants, the existing metro route failed to deliver the first and last connectivity. Around 32% of participants believe the current route is too short, while 21% believe commuters would have to switch to more than two modes of transportation to get to their destination if they take the Metro route.
In conclusion, the difference between expected ridership and actual ridership is huge, and the operational costs that went into completing this project haven’t been recovered yet. To close this gap between operational costs and expenses, serious steps are needed to be taken.
Some lesser known facts about Metro projects
Here are some amazing metro facts thanks to THEMETRORAILGUY!
Kolkata Metro is the oldest metro rail!
Pune Metro is the recent metro rail project!
Delhi Metro happens to be the largest metro system!
Ahmedabad Metro is the shortest metro system!
Delhi Metro has the highest ridership percentage!
Summary
Metro rails are the most coveted infrastructure in Indian cities. They are notable for helping people to move in a safe, fast, and easy manner. The public transit system connects hard-to-reach areas with the rest of the city, reducing traffic congestion as people drive less. Furthermore, with the introduction of metro rail, people's quality of life has increased by providing more economic opportunities to the less powerful sector of society.
Cemtech Infra Solution is a leading technology-first infrastructure and construction company. To develop a better and smarter future, we create efficient systems to construct roads, highways, railroads, bridges, metro structures, and other infrastructure. We believe in precisely constructing our products with the highest quality craftsmanship available.
We're always on the lookout for brilliant minds to join us in our effort to make the world a better place! Let us know your views on this blog at info@cispl.co
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