Near Miss is a 1991 annual story.
Henry grumbles about the trap-points outside the engine shed that are there to derail runaways that would otherwise collide with trains on the main line. The next day, a careless firelighter fiddles with his controls, causing Henry to roll away, smash through the shed doors, and puff out into the yards. Henry closes his eyes and fears the worst when he sees Gordon charging towards him. But thankfully, he is switched to the trap-points and derailed. Now Henry knows that trap-points have their uses after all.