The Eyesight Test is a short magazine story.
Thomas has missed a station on his line. The Fat Controller is cross and decides that Thomas needs an eye test. So, the Fat Controller stands on the turntable and holds up large cards with letters on them. Thomas passes the test easily and the Fat Controller then rearranges the letters on the floor to read "KEEP YOUR EYES OPEN", as it becomes apparent that the reason Thomas did not stop at the station is because he fell asleep.