The use of ALUMINIUM in RAILWAYS

Pragun Jindal Khaitan

Managing Director, Jindal Aluminium

Air pollution and greenhouse gas emissions that have resulted from the fast growth of human civilisation have threatened people for many years. As the transportation industry develops, energy conservation and pollution reduction are becoming increasingly important. The railways are a significant part of the transportation sector and our trains continue to be the favoured mode of transportation, carrying millions of passengers and tonnes of freight every year because of their more reasonable prices, comfort, and convenience. As a result, the railways have continued to improve their services and modernise their mechanics while beginning to prioritise energy conservation and reduce pollution. Finding its beginnings as a mode of transportation during the 19th century's industrial revolution, the railways have undergone continual development improving speed and safety while incorporating newer technology.

Reducing aerodynamic resistance, transmission loss, tyre rolling resistance, and weight are just a few strategies to increase energy efficiency and lower CO2 emissions. One effective option to make trains more efficient is a lightweight but robust structure. Metals, particularly cast iron and stainless steel, have historically been the primary material used in the manufacturing of transportation machinery, the railways included. Aluminium due to its weight, corrosion resistance, formability, high specific strength, and comparatively low price could replace the traditional metals.

Using aluminium reduces the overall weight of a rail car body by 50%.  It is one of the key raw elements that are enabling a transition for the railways. As a primary building material used in new age trains, aluminium now is also being used in contrails that join the train's floor to the sidewall, the ceiling, the sideboards, and the floor panels as well.

After successfully opting to use aluminium for its metro rakes, India is now keen on putting it to use in long-distance trains like the Rajdhani and Shatabdi Express trains as well.  While the Government of India has cleared the use of aluminium for next-generation trains that will be part of its vast railway networks spanning a total route length of 67,956 km, Japan and several European nations have already been enjoying the benefits of using aluminium train coaches for over 15 years.

Versatile benefits

Because there are fewer parts and strong corrosion resistance, aluminium is easier to build than steel. With its qualities of being lightweight, having strong corrosion resistance, having good formability, having high specific strength, and being relatively inexpensive, aluminium delivers a balanced performance. Aluminium weighs about a third as much as steel, but because of strength requirements, the majority of aluminium parts used in the transportation industry weigh around half as much as the equivalent steel parts.

Aluminium has several benefits over other metals in applications ranging from rapid transit and suburban rail systems to high-speed trains and freight trains. In rapid transit and suburban rail systems, where trains must frequently stop, significant cost savings can be realised by using aluminium body coaches since less energy is used for acceleration and braking. According to a study published by Aluminium Insider, new aluminium wagons' energy consumption can be reduced by up to 60% by combining the light-weighting of trains with other similar techniques. On average, 5 tonnes of aluminium are used by each of these wagons.

Green future

Aluminium is the future of railway architecture, be it with the coaches and wagons or even other signalling infrastructure and station furniture. Since aluminium is corrosion-resistant, it has the potential to extend the lifespan of railway coaches lasting nearly 40 years with lesser maintenance. The existing trains in use by the Indian Railways have a 35-year lifespan with aluminium adding another 5 years. This also ensures that coaches and wagons made of aluminium benefit from a higher salvage value when the metal is put to reuse at the end of its life cycle. The other benefit that makes aluminium a sought-after metal is that the production process is faster and coaches or wagons can be delivered within a lesser time frame. 

Even though it is asserted that aluminium initially costs more than standard coaches and wagons, the railways will undoubtedly benefit in the long run. Aluminium wagons can carry 7-8% more weight up to 70 tonnes than a stainless-steel wagon, which can only transport about 65 tonnes. Finally, any project that generates a rate of return of more than 15% is seen as commercially feasible by the Indian Railways, which have made enormous strides in their offerings to their users. But with a higher rate of return of 25-30%, aluminium is a material that can be an effective collaborator in a bright future for railways all over the world.

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