On 5 June 2012 (World Environment Day), a very different kind of train steamed into New Delhi’s Safdarjung Railway Station. It was the Science Express. The train was sparklingly clean, with its air-conditioned interiors and exhibits having been completely redone according to the theme for the year.

In 2012, that theme was aligned to the United Nations’ focus on biodiversity and the prevention of desertification across the globe, so the train was called the Science Express Biodiversity Special.

After a few hectic days packed with visits from schoolchildren, the train was scheduled to set off on a unique journey.

Just five years earlier, in 2007, the Science Express had been launched as a joint project between India and Germany, with Prime Minister Manmohan Singh and German Chancellor Angela Merkel at the flag-off.

Since then, this 16-coach museum-on-wheels had been travelling across India, averaging between 15,000 to 20,000 km every year. It stopped at over fifty stations so that school kids could visit and explore the exciting world of science and technology.

But there was something extra special about the Science Express in 2012. It came with a voting booth for just kids no adults allowed! And can you guess what the children across India were...