Friday , 19 July 2019

Metro Rail System Need for Standardisation

An increasing number of cities in India have opted for metro rail as the choice of mass rapid transit system. The author takes a look at the issues faced by vendors supplying systems for the metro rail in India as well as innovation and trends in metro rail and mainline rail systems.

Urbanisation in India is increasing rapidly – about 40% of the population – 600 million people are expected to live in cities by 2031, with about 30 cities having population above two million. There is an urgent need to implement efficient mass transit systems in these cities. Options for MRTS systems include Metros, LRT/Trams, monorail and BRTS. The choice for a particular mode should be based on capacity requirements and assessment of future growth.

The 12th Five-Year Plan, envisages an investment of 1,30,276 crore for various modes of urban transport. Three cities in India have operational metro lines, nine are under construction and another eight are being planned. Massive investment to the tune of 1.3 trillion is required to execute these projects. Possible modes of funding include 100% Central/State government funded (e.g. Kolkata metro N-S Line), combination of government funding and loans from multilateral agencies (eg: DMRC), PPP projects with viability gap funding (VGF) from state government (eg: Hyderabad) and 100% private funding (light metros like RapidRail Metro in Gurgaon)

A problem faced by vendors is that different metro systems in India have widely varying technical configurations leaving no scope for adapting existing solutions. A process of standardization needs to be adopted in India, similar to that in China where metro systems are categorized into Classes A,B, and C depending upon capacity and performance requirements. Standardization provides many benefits: It avoids re-inventing the wheel as it enables the use of existing solutions by optimizing them. It reduces costs – design & engineering, production tooling and maintenance costs. It also results in faster project execution due to quicker design approvals and faster manufacturing, construction/installation etc. Standardization also encourages localization by manufacturers and establishment of a local supply chain.

Innovations and Trends

Increasingly, as the metro revolution extends from large metropolitan cities to Tier-2 cities like Kochi, Nagpur and Lucknow, there is a need for an integrated light metro solution which can be constructed quickly in congested areas with reduced construction and maintenance costs. Such a solution should:

• Be a turnkey system which provides a single point of responsibility for construction and implementation so as to offer complete optimisation in terms of interfaces between different sub-systems and their, design, construction time and operations and maintenance

• Be able to cater to traffic loads between 15,000 to 45,000phpdt

• Be able to negotiate sharp curves of radius typical to Indian cities

• Have low footprint in order to minimise land acquisition issues for right of way and construction space

• Be driverless with low energy consumption to reduce operational costs

• Be non-proprietary with standardised solutions for low maintenance costs

While monorails are being contemplated as an alternative to light metros in many Indian cities, they suffer from several drawbacks which become more apparent as the system ages. Because monorails are used in very few cities globally, there are a limited number of suppliers who manufacture systems that are mutually incompatible with very high operations and maintenance requirements. Reduced competition therefore leads to inflated costs calculated on per passenger km basis. Moreover, since the operator is tied up with a single supplier, maintenance and procurement of spare parts becomes expensive. Rolling Stock for monorails is also difficult to extend when more passenger traffic requires a high passenger carrying capacity. Add to this the fact that passenger evacuation in case of emergencies often involves complicated arrangements, situations could arise where passenger safety might be compromised.

By contrast, light metro systems have been implemented extensively around the world over in the past half century. This has resulted in systems which are highly optimised from the point of view of performance, energy consumption, operation and maintenance costs. For example, Alstom’s turnkey metro light metro solution – AXONIS – offers several innovations which leverage cutting edge developments in the railway industry:

The viaduct is constructed from pre-cast modules which are easy to transport and ideal for swift construction. High manoeuvrability means that it can be constructed in narrow streets with curve radius of up to 45m. The rolling stock has been made lighter and consumes less power by up to 30%. When used in combination with HESOP – a reversible DC sub-station – it enables almost all electric energy recoverable from trains with regenerative braking systems to be fed back to the electric grid. These trains also use CBTC signalling system which makes headways between trains very less and significantly increases the traffic capacity of the corridors. Driverless metro trains with up to 75 seconds headways are possible because of the new CBTC signalling technology.

Innovations and Trends – Mainline and Suburban Railways

While the metro rail sector has been undergoing a revolution in India over the past decade, the state of our suburban and mainline railway systems leaves much to be desired. Several innovations, which can vastly improve system performance, but have only a marginal impact on cost, could be implemented:

• Energy efficient system design: This has been achieved by improving the effectiveness of traction systems, articulated architecture of train sets, traction motors with permanent magnets and improved efficiency. Traction with re-generative braking using high discharge capacitors and flywheels are used to reduce energy consumption by 10-15%. The trains operate in dual (hybrid) mode which reduces energy consumption by about 40%. Use of lithium ion battery instead of conventional lead acid battery allows for lighter weight and better efficiency. Energy consumption in the trains have been found to vary up to 35%, depending on the driver and driving conditions. On the other hand, driverless trains and Driver Advisory Systems which continuously calculate optimum speed based on inputs from track, rolling stock and control centre have been found to have 10-15% savings in trial operations. Also, the trains use solar energy for auxiliary systems such as lighting, displays & LED and HVAC. These auxiliary systems normally account for around 20% of the train energy consumption. Reducing train weight can also have a substantial impact on energy consumption. For example, the high-speed train AGV consumes the equivalent of 0.4 litres of fuel per 100 km. The next-generation metro train in Paris consumes 30% less electricity. The weight of its high-speed trains and regional trains has reduced by 10-15%.

• Eco friendly coaches: Coaches can be designed to eliminate harmful substances and materials and instead use biomaterials from renewable resources, e.g. Alstom trains use up to 95% recyclable materials. The trains could also be fitted with LED lightings & LCD displays for improvement in functionality as well as for added passenger friendly features.

• Double decker trains: Another innovation that could be introduced in mainline/suburban trains in India is double-decker trains. A double decker costs marginally more than a single level cars but it can increase the capacity of each car by 30%. This allows for a six car configuration to have a capacity of 120,000 PHPDT. Also, even with a double deck the trains, with sharp bevelled roofs, can be designed to fit into existing tunnel clearance levels. This would require some modifications such as removal of luggage racks and a lower ceiling height. Such double-decker trains could be introduced in existing suburban / urban rail links in cities such as Mumbai and Chennai.

• Disabled friendly access: A feature that could be introduced in metro trains is allowing easy access to disabled commuters, a demand that is rapidly gaining voice in the country. Such trains will however require facilities such as wheelchair access ramps, size and allocation of handrails, better passenger information systems and other devices.

Increasingly however, a trend is being observed where a mass transit system is required to perform the dual role of a city-wide as well as a suburban rail system. The trains required in such a system should be capable of running on both lines with different voltage levels, speed profiles and signalling systems. For example, Citadis Dualis is a tram-train from Alstom which permits seamless daily journeys between city-centres and suburban centres without having to change their transportation mode. It runs equally well on tramway networks and on regional rail networks with compatible power tension on wires, signalling and tracks. It has a reinforced structure in the event of a crash that conforms to the latest safety standards. Its collapsible coupling enables better shock absorption in stations. The structure of the tram-train offers numerous advantages.

Development of standardised metro rail systems can help lower costs, expedite project execution times and encourage localisation. For example, a light metro turnkey rail solution with its relatively short execution time would be ideal for Tier 2 cities in India where narrow, winding streets require systems that have low footprint and can negotiate sharp curves. Simultaneously, our suburban and mainline systems could also be vastly improved by incremental changes through energy efficient design, eco-friendly coaches and better amenities for disabled passengers. So although commendable work has been done over the past decade on the urban transportation front, persistent efforts are required to meet the challenges that still lie ahead.

Mangal Dev
Director, Business Development – India and South Asia
Alstom Transport

Mangal Dev, an Engineering graduate from IIT, Kanpur, has led important projects for Alstom such as the 800 electric locomotives Joint Venture at Madehpura with the Railway Ministry. He also launched Alstom’s Metro business in India which bagged the Chennai Metro Rolling Stock and Track work projects.