Where did Montag go after fleeing Fabers house?

Depends what part your meaning by. If it's the part when Faber has just shown him the ear piece then Faber is telling him to go the fire station to hear the voices of the firemen. But if it's when Montag is being hunted down by the Hound, then Faber is telling him to "follow the railroad tracks" in order to start a new world with his new friends Granger and the others.