Long ago, I read a book in which the main character's father worked on the railroad, and had developed a pace where every step was the exact distance between two ties. This mental image always irritates me because that distance is *not* constant, and as soon as you pick up a rythm, you hit a tie that is off by just enough to make you have to reset your pace. And yet, EVERY time I walk on a railroad, that image comes to mind. Even though I have long since forgotten what book it was, which is a large part of the annoyance, come to think of it.