British online friend: "Saw a flying banana tonight. I only noticed because of the purple light shining upwards"

Everyone: ???

"We have track measurement trains. They run around, checking the tracks for faults, the power cables, etc

They're bright yellow. So they're nicknamed the Flying Banana, as a joke on the Flying Scotsman

Night time they have this blue laser that scans the overhead wires. It creates this giant glow you can see when it moves"

@GreenSkyOverMe reminds me of how the sacramento kings' arena installed a "beam" that lights up every time the team wins a game

https://en.wikipedia.org/wiki/Light_the_Beam#%22Light_the_Beam!%22_and_2022%E2%80%9323_season
Light the Beam - Wikipedia