He’d been blind, and the clinic had given him his sight back. When the train went into a tunnel and everything went black, the glowing tips of the smokers’ cigarettes told him his eyes still worked.
Back when trains had smoking carriages, a man takes the train home from a clinic in Switzerland. Afterwards he says that if he’d sat in a non-smoking carriage he would have killed himself. Why?
Give me a hintThe hint
What happened to the light?
Reveal the answerHide the answer
He thought he’d gone blind again in a tunnel
Source: Jed’s list of situation puzzles, No. 1.87, credited to David Van Stone