Pretty simple. A train wreck is a week when no one deserves to survive: (nearly) everybody stinks up the place. TPTB don't so much declare a train wreck as put one in motion by accident or on purpose through picking an impossible (or improbable) theme, like Queen. (I can hear Richard Kiley in the background singing 'To theme, the impossible theme.'
So far this season, the train wrecks have probably all been accidents. If tonight though, meets a lot of folks' expectations and is a complete cock up, some of us suspect it will have been by design.
A somewhat unrelated thought, how about Chris trying 'Crazy Little Thing?' Does anyone know if any alt. rock band has done a brooding cover of this song, yet?
(n.b. to flkofguls, the above is how one defames with a fine line brush, rather than an eight inch roller.)
The Other Mickey