Electrified rail places #74 on Drawdown’s list of climate solutions, with the potential to reduce atmospheric carbon dioxide by 500 megatons by 2050. While expanding rail lines around the world from 166,000 to 621,000 miles (267,150 to about one million kilometres) would cost US$809 billion, 30 years of use would see $314 billion saved, with a further $770 billion in savings over the life of the infrastructure.

While “the number of electric trains is increasing,” writes Drawdown, the extent to which the transition from diesel reduces GHG emissions will depend on grid efficiency. “As electricity production shifts to renewables, rail has the potential to provide nearly emissions-free transport,” the authors state.

Meantime, continued efforts to boost mechanical and operational performance are helping to further improve fuel efficiency. Increasingly, rail operators are replacing old locomotives with hybrid diesel-electric engines, with efficiency gains “similar to those of hybrid cars,” introducing regenerative braking systems to capture energy that would otherwise be lost as heat, and using “‘stop-start’” technology to curb fuel use while locomotives are idling.

Lighter, more aerodynamic cars, lubricated rails, and engineering software to control train speed and timing are also helping to decrease fuel use—to the extent that a diesel locomotive today can carry a ton of freight 450 miles (725 kilometres) on a gallon of fuel, compared to 235 miles (375 kilometres) as recently as 1980. With rail accounting for 3.5% of transport sector emissions—more than 260 million tons of CO2 in 2013—“it is time for the whole industry to follow its most efficient leaders,” Drawdown states.