A train line in western Switzerland now carries two kinds of traffic: passengers above, and sunlight below.

On a 100-meter stretch of active railway near the village of Buttes, 48 solar panels sit between the rails, low enough for trains to pass over them and removable enough for crews to take them away when the track needs work. The installation, developed by the Swiss startup Sun-Ways, is small. Its 18 kilowatts of capacity could generate about 16,000 kilowatt-hours of electricity a year, roughly the annual use of a few European households.

But this is just a pilot program. If the system works safely on a busy rail line, it could point to a new way of expanding solar power without covering farmland, forests or mountain slopes with panels. That’s perhaps important in Switzerland, more so than in other places, where renewable energy is urgently needed, but new solar projects can face resistance when they move into cherished landscapes. NIMBY is sadly a global phenomenon.