Monorail or Metro Rail: the pros and cons

NEW FACILITY COMING: Work on the Metro Rail in progress on Jawaharlal Nehru Road on Tuesday. The proposed monorail is expected to supplement this service. Photo: S.S.Kumar  

With the State government recently announcing a proposal to construct a crisscrossing network of monorail corridors in the city that would be 300 km in length, Chennai has been put on the road to having the largest and most extensive monorail network in the world. Even if only the 111-km-long Phase-I of the project materialises, it will dwarf all other monorail networks in the world.

There are fewer than 20 monorail systems in Asia, of which 10 are in Japan. The longest operational monorail line in the world is a 23.8-km corridor in Osaka. Even the Monorail Society, an international advocacy body, describes Chennai's plan as “ambitious” and “staggering”.

On the other hand, Metro networks are in operation in 178 cities around the world, with the largest being the 430-km-long Shanghai Metro.

A senior government official said that while construction on the 45-km Chennai Metro Rail will continue, expansion would be put on hold due to the “high cost.” A special purpose vehicle to implement the monorail project is likely to be set up shortly, he said.

Capacity to cost

Experts note that a monorail is usually confused with cable car, light rail or tramways. A monorail, in simple terms, is an electric-powered bus that runs on an elevated concrete beam. The Mumbai Monorail, which is the only such system that is currently under construction in India, is a four-car train, with a capacity of 140 passengers per car. The maximum capacity of the system is 10,000 passengers per hour per direction.

The capacity of a Metro system, which can accommodate up to nine cars, is about three to four times more. Thus, the capacity-to-cost ratio is better for a Metro system, even though the per kilometre construction cost is more.

A senior official of Scomi International, a Malaysian monorail manufacturer which is involved in the Mumbai project, says that it comes down to identifying the most economical solution for an expected passenger volume. “For cities that have a population of less than three million, monorail is the ideal mode of transport. For denser cities, monorail can ideally serve as the feeder line that brings passengers in and takes them out of the Metro network.”

He says that monorail corridors should be ideally 15 km to 30 km in length and run through “congested neighbourhoods with narrow roads” where high manoeuvrability would be required. Advocating the Kaula Lampur model, the official says that bus routes inside the city could be replaced by monorail corridors. “The buses can then be used in suburban areas to feed the monorail network. This will also give more space for private vehicles on city roads.”

N.S. Srinivasan, a former Director of the National Transportation Planning and Research Centre, says that a monorail system is best suited for feeding suburban areas. “It can be built very quickly and can extend into outer areas such as Porur, Sriperumbudur and Ambattur. Monorail is ideal for building a regional network. But within the city, the system will reach its capacity very fast.”

He says that a sustainable urbanisation strategy must involve dispersal of the population away from the city core and the dream of extending mass rapid systems such as suburban rail and Metro Rail into outer areas is just not economical. “Revenue from mass rapid systems can meet only recurring cost. The capital cost has to be written off. Monorail is much better when you are looking at a solution not just for the city, but also its rapidly expanding suburbs.”

However, advocates of bus rapid transit systems, such as Dinesh Mohan of IIT-Delhi, say that if cost is a major criterion, then upgrading bus networks is the best option. “Building a dedicated bus lane costs just Rs.10 crore per km. There can be a bus station every 400-500 metres, thereby ensuring the largest area of coverage among any transit system.”

For example, the Delhi Metro, despite its reach, accounts for only five per cent of the daily trips undertaken in the national capital due to the 1-km distance between each station. Mr. Mohan adds that cities must concentrate on creating pedestrian footpaths and cycle tracks, which can be built at less than Rs.1 lakh per km and would benefit a wider section of the population.

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Printable version | Sep 18, 2021 6:15:48 AM |

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