In Fahrenheit 451, what does Montag do when the train stops?
At the beginning of Part II, "The Sieve and the Sand," Montag is trying to read the Bible on the subway. He compares reading to trying to fill a sieve with sand, as he tried to do when he was young. He is trying to memorize the words in the Bible, but the advertisements keep coming on over the loudspeaker of the train for goods like "Denham's Dentrifice" when Montag is trying to concentrate on Biblical images such as the lilies of the field. As a result, he loses his patience entirely, and the radio on the train gets louder when he is screaming about the Bible: "the train radio vomited upon Montag, in retaliation, a great tonload of music made of tin, copper, silver, chromium, and brass" (page 79). The louder he speaks, the louder the hideous music in the train plays. By the time his stop is called, his voice has quieted, and the radio on the train whispers in response. While everyone else is sitting in submission, Montag rushes out of the door at the last minute and runs through the tunnels on his way to Faber's house. He runs rather than taking the escalator to feel his own power and relax his tense muscles.
Just prior to the train making a stop, Montag has been trying to read and "absorb" the Bible, but has been unable to do so because of the advertisements playing over the train's speakers. He ends up screaming at the speakers and telling them to "Shut up! Shut up!" When the train stops, Montag stands, then leaps out the train's doors as they start to close. When he is out of the train, he begins to run. At that point, the book segues into his arrival at Faber's house.