One of the hardest climate puzzles to solve is how to cut greenhouse gases from airplanes. International travel is essential, but zero-emission flights are decades away. In Europe, where transport accounts for quarter of emissions, policymakers may have a solution: get people to take the train instead.

Countries including France, Germany and Austria are spending billions of euros to remake the continent’s aging railway system. Their leaders are hoping to spur a renaissance in international train journeys, especially as the coronavirus pandemic ebbs and travel picks up again. After all, hopping on a train is often more convenient than flying (for one thing, there’s no airport security).

The European Union has an interest in pitting modes of transport against each other—it could push operators to find ways to lower their climate impact without passing costs on to the consumer. It’s a question of making rail more attractive, “instead of banning or disincentivizing aviation,” says European Transport Commissioner Adina Valean.

A revamped Vienna-to-Paris sleeper service, operated by Austria’s state rail company OeBB in partnership with Germany’s Deutsche Bahn, is set to start next year. While the 1,000 kilometer trip will take eight hours more than going by plane, it’ll generate a tenth of the emissions.

The new night train routes are just the beginning. European policymakers plan to roll out more cross-border rail lines over the coming decades as they seek to zero out emissions by 2050.