Environmental degradation along the route, dislocation of people, noise pollution, and regionally imbalanced development are potential pitfalls.

The flurry of activity that accompanied French President Francois Hollande’s visit to India last month extended beyond the Republic Day parade, at which he was chief guest. Among the toasts, speeches and statements were agreements on rail — including a feasibility study on upgrading the Delhi-Chandigarh line to a semi-high speed of 200 kmph, so the entire distance is covered in 1.5 rather than 3.5 hours. This marked another step in India’s race to roll out high speed rail across the country.

High Speed Rail means different things in different contexts.

One widely accepted definition applies to new lines running at 250 kmph and above, and existing lines that are able to run at 200 kmph and above. High speed rail programs have been successful in Japan, China and several European countries such as France, Germany and Spain. The benefits include reduced journey times that impact individuals and business, connectivity benefits to populations and markets, increased passenger comfort, mode shifts from more polluting air and road transport and consequently, lower road congestion. High speed rail can create agglomeration benefits i.e., benefits that accrue from the clustering together of firms and labour markets, and regeneration benefits for an area. The actual construction also provides an opportunity for employment and the potential for technology transfer.

The high speed lunch, like all other lunches, is not free. Environmental degradation along the route, dislocation of people, noise pollution, as well as regionally imbalanced development are potential pitfalls that need to be carefully negotiated. How the high speed line interacts with existing transport choices is also crucial for the strength of the overall case.

India has been toying with the idea of high speed trains for fifteen years. The High Speed Rail Corporation (HSRC) of India was set up by the government in 2012 to design and implement the country’s high speed projects. Through this, feasibility studies for various segments of the ‘Diamond Quadrilateral’, a proposed high speed network spanning the country, connecting Delhi, Mumbai, Chennai and Kolkata, were initiated.

Simultaneously, the government has pushed ahead with plans to develop a Rs.980 billion, 505 km segment between Ahmedabad and Mumbai on which it will run “bullet” trains, as high speed trains are often called. A joint feasibility study was submitted by the Indian Railways and the Japan International Cooperation Agency (JICA), the Japanese government’s official aid agency, in September last year, and a pact signed between Prime Minister Narendra Modi and his Japanese counterpart, Shinzo Abe, during Mr. Abe’s visit to India in December 2015. Tickets will cost approximately Rs.2,800 and the journey will take approximately two hours.

This bullet train has brought into focus the parameters associated with high speed rail that need careful consideration. The United Nations Environment Program (UNEP) and the Technical University of Denmark (DTU) published a study on the Ahmedabad-Mumbai train line last year. The report points out that the region in question is highly active economically. It is also a high density corridor (18 million passengers in 2010); connecting dense urban areas has been a key success factor for high speed rail in China and Europe. Travel demand between 2010 and 2050 is expected to increase four-and-a-half times to 58.2 billion passenger kilometers according to the study. To determine the effects of the bullet train, the study presents two scenarios over the 2010 – 2050 horizon; a Business As Usual (BAU) scenario and a High Speed Rail (HSR) scenario.

The results of the simulation indicate that conventional rail use increases, albeit insignificantly, in the BAU situation; better roads increase road usage, especially for inter-city travel. Overall, road transport’s share reduces because road trips by bus and car between Mumbai and Ahmedabad fall with an increase in relative travel time compared to other modes; this fall is partly offset by increased intercity travel.

In the HSR scenario, high speed trains cater to one-fifth of the total travel demand in 2050, and the growth rate of air travel slows, because of competition from high speed trains. The HSR solution is also cleaner; CO2 emissions in 2050 are also lower by 0.2 MT and further emission drops are possible with decarbonisation of electricity, according to the UNEP. In general, per passenger km, high speed rail has lower greenhouse gas (GHG) emissions than road or air transport. It also supports lower emissions over the longer term as road and air passengers shift to trains. However, as the UNEP-DTU study says, there is currently debate on the impact on short term emissions, which may be high owing to embedded emissions (in the construction and manufacturing process). The country definitely needs high speed rail and is already late in that regard, but the cost and speed need to be carefully considered, according to Vivek Sahai , former Chairman of the Railway Board and currently based in Mumbai with the Observer Research Foundation, a think-tank.

“Do we really need a train speed of 350 kmph? Speaking as a technocrat, I say we should discover the speed at which the train is profitable. If it is 350 kmph then go for it, I have no problems with that,” Mr. Sahai told The Hindu.

Factoring in distances, travel patterns, ticket costs and purchasing power, Mr. Sahai feels that high speed trains in India are likely to be more successful if they had average speeds in the 200-250 kmph range, as opposed to the planned 320 kmph speed of the Ahmedabad-Mumbai bullet train. This will extend the duration of the trip by a marginal amount, but will bring down construction and operation costs significantly, since these costs increase rapidly for speeds above 250 kmph . The GHG impact above speeds of 250 kmph is also not known with certainty.

Higher speeds imply higher costs which may then necessitate higher ticket prices so that the service is commercially viable. This, ironically, could mean a loss of ridership to air travel, making the train less profitable.

In terms of timetabling as well, Mr. Sahai said, running a high speed train at slower speeds, for instance in the 200 – 225 kmph range over longer distances (such as Delhi-Mumbai or Delhi-Kolkata) will allow them to be run as sleeper services rather than tedious daytime journeys with awkward departure times. If the government goes ahead with its Diamond Quadrilateral plan, there will be high speed links in the 1,300-1,450 range, such as Delhi-Mumbai, Delhi-Kolkata and Mumbai-Chennai as well as links of around 2,000 kms (Delhi-Chennai and Mumbai-Kolkata). A significant difference in distance alters the economics and business case for high speed rail markedly.

Long distance routes compete with air travel; individuals willing to pay for a long distance high speed rail ticket are likely to prefer a flight, given the journey time savings. If the 500 km journey between Ahmedabad and Mumbai is about Rs 2,800, then the Delhi-Chennai journey is likely to cost Rs.11,200. A one way flight for this journey booked ten days in advance costs in the ballpark of Rs.4,000, suggesting challenges for the Delhi-Chennai high speed model.

“Each country and environment has its own constraints,” Jean-Marc Tessier, chief of the main line and locomotive division of Alstom, a French multinational railway systems and train manufacturer, told The Hindu. “The optimal speed depends on the complete business case that you have to set up for the country. The best solution depends on your return on investment compared to other means of transportation.” Alstom, which developed the TGV, France’s high speed train, has a growing presence in India. The head of Alstom’s transport division, Mr. Henri Poupart-Lafarge, had said in 2014 that India was five to ten years away from high speed rail and ought to first upgrade existing infrastructure.

“When you put in place a very high speed system in a country, it is important that you connect it with something that is at the same level of efficiency. And the message of my president [ Mr. Poupart-Lafarge] was to say, you cannot just focus on one high speed line and do nothing with the rest, because the system is not going to work efficiently,” Mr. Tessier said, explaining the Alstom chief’s comments.

For instance, if the first 500 kms is covered in two hours using a high speed train and the remaining 50 kms via another mode is covered in another two hours, then it weakens the case for using high speed rail for that trip, when a flight may be a better option, time and price considered.

Increasing the operating speed of existing lines would be one possible way forward for transforming India’s rail systems, according to Mr. Tessier. High speed lines require huge investments and cause long term demographic and economic impacts. Their success depends on getting a comprehensive, context-specific optimal solution; at the very least this means getting speed, pricing, and distance right.