Invisible - Pete Hautman

You could say that my railroad, the Madham Line, is almost the most important thing in my life. Next to Andy Morrow, my best friend.
Lots of people think Doug Hanson is a freak -- he gets beat up after school, and the girl of his dreams calls him a worm. Doug's only refuge is creating an elaborate bridge for the model railroad in his basement and hanging out with his best friend, Andy Morrow, a popular football star who could date any girl in school. Doug and Andy talk about everything -- except what happened at the Tuttle place a few years back.
It does not matter to Andy that we live in completely different realities. I'm Andy's best friend. It does not matter to Andy that we hardly ever actually do anything together.
As Doug retreats deeper and deeper into his own reality, long-buried secrets threaten to destroy both Doug and Andy -- and everything else in Doug's fragile world.