Well if this helps instead, people park on their yards every day with hot exhausts and catalytic converters. And some of us with old gravel driveways have a little grass right where we’re actually supposed to park, lol.
But yeah you’re right that when they decided to make that route so nice and green, they signed up for regular maintenance!
They're trams in the city, so relatively slow. Live and maintained vegetation has too much water to burn: boiling away the water takes more energy than the fuel provides.
It's probably also got those pop-up sprinklers, so if a fire does happen, you just turn on the water.
Covering a city in tram lines and sprinkler systems so you can keep up a fairy tale aesthetic with more grass isn't practical. Just do gravel like the train lines and accept that keeping it pretty would be an irresponsible use of water in our increasingly frequent droughts.
It completely depends on the region, though. The grassy tram pic is from Helsinki, which is a plenty moist region that I think is generally predicted to get more rain with climate change. Sustainable urban design should be tailored to the context.