An anonymous reader shares a report: India's massive diesel-guzzling railway network is getting serious about its experiments with solar. On July 14, Indian Railways rolled out its first train with rooftop solar panels that power the lights, fans, and information display systems inside passenger coaches. Although the train will still be pulled by a diesel-powered locomotive, a set of 16 solar panels atop each coach will replace the diesel generators that typically power these appliances. The railways estimate that a train with six solar-powered coaches could save around 21,000 litres (5,547 gallons) of diesel every year, worth around $108,000. In 2014, Indian Railways consumed 2.6 billion litres of diesel, accounting for around 70% to the network's total fuel bill of $4.4 billion. The first of these trains will be pressed into service on the suburban railway network of New Delhi, one of the world's most polluted cities, before two dozen more coaches are fitted with similar rooftop solar systems. Retrofitting each coach with these system, including an inverter to optimise power generation and battery for storing surplus power, costs around $14,000.