I am trying to find this book that I read in high school. It is about two friends who are neighbors. Throughout the book you see that the two have a very strange relationship and at the end you find out that one of this kids was killed in an accidental fire that the two started. Please help me find this book! I'd love to read it again.
"Invisible" by Pete Hautman

Dougie talks with his best (and only) friend, Andy Morrow. Athletic, popular Andy is very different from socially inept Dougie, yet the two find things to talk about. They discuss everything - except for what happened at the Tuttle Place three years ago. It is evident that Andy and Dougie's friendship (which adults are afraid of) is not what it seems to be at first: not only is Andy absent when Dougie needs him most, he pressures Dougie into stalking a classmate, Melissa Haverman, and making a bomb threat via the telephone. When Dougie's psychologist finds out that he's been skipping sessions and hiding his medications, the teenager is forced to remember that fateful night at the Tuttle Place. The truth is that Andy is dead, a victim of the fire they accidentally set to the house.

In the end, he sets fire to his beloved bridge while in the basement, becoming a burn victim at the hospital. Andy then visits him, promising to return.

However, it is debatable as to whether Dougie died or not, since he was hospitalized at the "Madham Burn Unit," the name of his self-built town with his railroad of matchsticks. He also mentions that the hospital smells of burning plastic, referring to the plastic people in Madham, present when he set the town on fire, and that he wants to find his grandfather, to see if he is mad about the train. Whether it is his imagination that leads him to smelling burnt plastic and seeing "Madham Burn Unit" or he has died and Madham Hospital is his place of rest is not revealed"

"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....I guess you could say that I'm not only disturbed, I'm obsessed.
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 building elaborate model trains in his basement and hanging out with his best friend, Andy Morrow. Andy is nothing like Doug: He's a popular football star who could date any girl in school. Despite their differences, Doug and Andy talk about everything -- except what happened at the Tuttle place a few years back.

As Doug retreats deeper and deeper into his own world, long-buried secrets come to light -- and the more he tries to keep them invisible, the looser his grip on reality becomes. In this fierce, disturbing novel, Pete Hautman spins a poignant tale about inner demons, and how far one boy will go to control them"