Do the locomotion

Rail travel produces more than a third less emissions than road transport — even though trains carry 7% of traffic, they emit just 0.2% of the carbon monoxide, 2% of nitrogen oxides and 1% of the volatile organic compounds. Although electric passenger trains are relatively green, most of the world's trains are used for haulage and run on diesel. In the latest of our Future Transport series, Duncan Graham-Rowe sees trains switching to a greener track.