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.
The country aims to have 36%-38% of its energy come from renewable sources by 2030, while slashing overall energy use.
Tokyu Railways has sought to publicize its effort with posters and YouTube clips.
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."
"I had no idea," he said.
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.
In a sense, he said, "I lead a very green life."
