Solar Powered rail coaches with flexible solar panels installed on roof (Science Express Train)

The Indian Railways being one of the largest railway networks in the world operates around 12,000 trains per day. It is also one of the largest consumers of diesel in the country, with an annual consumption of 2.7 billion litre, which includes traction requirement as well as coach lights, fans, AC, etc. The train rooftops remain continuously exposed to the sun during the day 24*7, except during cloudy days. In Indian conditions, the number of sunny days is 300 (out of a total of 365 days in a year). Thus solar energy was being wasted, In fact it was further heating the coaches resulting in increased cooling requirement. If the train roof tops could be covered by specifically designed flexible solar panels, then the train will become a mobile source of generating electricity (solar energy) from solar radiation.

The past projects implemented on the railway coaches require MS frame to be mounted on the roof which is usually done by puncturing the roof of the railway coaches. This may have the impact on the life of the coach. Also this mounting method leads to additional weight of around 1 ton per coach and also increases the height of the railway coaches by 7 inches. This addition to height and weight increase drag leading to more fuel consumption during train running.

The need of hour was to best utilize the railway coach roof space for generating the electricity through solar without increasing the traction load.  It is also imperative that the electrical load of the coach may also be reduced by using energy efficient devices with smart sensors to efficiently use the electricity generated from the solar power plant on the railway coach roof.  It is also expected that by covering the roof using the solar panels the coach temperature may come down by 2 deg C giving comfort to the passengers.

The flexible crystalline solar panels were designed especially for the railway coach roof.  The fail-safe pasting technology is used to fix the panel on the railway coach roof. The pasting technology consists of three components, special type of tapes along with the adhesives is used to affix the flexible solar panel on the railway coach. In order to provide safety to the flexible solar panel a special type of tape is used to cover all the edges of the flexible solar panel. The use of the specialised pasting technology ensured proper performance of the plant at a wind load of 200km/ hr (with train running at 100km/hr) and roof surface temperature of 60 deg C to 70 deg C.

This innovative technology was used for the first time in the country. There have been no. of experiments with conventional solar panels. The flexible solar panel to cover the full roof of the railway coach with specialised pasting technologies which was done for the first time.  



India has started a new chapter in renewable energy on 15th October 2015, the birthday of Dr. Kalam. It has started Climate Action Special - Science Express Train that will cover 20 states and give knowledge about conservation of environment through use of Science and Technology.

This train has flexible Solar Photovoltaic Panels manufactured in India for the first time by the pioneer company of Solar PV in India - Central Electronics Limited, a government of India, Dept of Science and Technology CPSU.