Tokyo's Shibuya is famed for its Scramble Crossing, where crowds of people crisscross the intersection in a scene symbolizing urban Japan's congestion and anonymity. It may have added another boasting right. That means the carbon dioxide emissions of Tokyu's sprawling network of seven train lines and one tram service now stand at zero, with green energy being used at all its stations, including for vending machines for drinks, security camera screens and lighting. Nicholas Little, director of railway education at Michigan State University's Center for Railway Research and Education, commends Tokyu for promoting renewable energy but stressed the importance of boosting the bottom-line amount of that renewable energy. 'I would stress the bigger impacts come from increasing electricity generation from renewable sources,' he said. 'The long-term battle is to increase production of renewable electricity and provide the transmission infrastructure to get it to the places of consumption.' The technology used by Tokyu's trains is among the most ecologically friendly options for railways. The other two options are batteries and hydrogen power. And so is it just a publicity stunt, or is Tokyu moving in the right direction? Ryo Takagi, a professor at Kogakuin University and specialist in electric railway systems, believes the answer isn't simple because how train technology evolves is complex and depends on many uncertain societal factors. Tokyu paid an undisclosed amount to Tokyo Electric Power Co., the utility behind the 2011 Fukushima nuclear disaster, for certification vouching for its use of renewables, even as Japan continues to use coal and other fossil fuels. Such steps are crucial for Japan, the world's sixth-biggest carbon emitter, to attain its goal of becoming carbon-neutral by 2050. The renewable sources driving Tokyu trains include hydropower, geothermal-power, wind power and solar power, according to Tokyo Electric Power Co., the utility that provides the electricity and tracks its energy sourcing. Tokyu has more than 100 kilometers (64 miles) of railway tracks serving 2.2 million people a day, including commuting 'salarymen' and 'salarywomen' and schoolchildren in uniforms. Since the nuclear disaster in Fukushima, when a tsunami set off by a massive earthquake sent three reactors into meltdowns, Japan has shut down most of its nuclear plants and ramped up use of coal-fired power plants. Still, Ryuichi Yagi, who heads his own company that used to make neckties but has switched to wallets appeared surprised to learn he was riding on a 'green train.' Yagi switched his business because of Japan's 'cool biz' movement. It encourages male office workers to doff their suits for open-necked short-sleeve shirts to conserve energy by keeping air conditioning to a minimum in hot summer months.