Many gamers are now happily playing their new Spirit Tracks game, but not so for those who ordered from some major retailers such as Gamestop. Try taking your preordered game from there and you will encounter a problem, in the form of them not giving you the game.
Apparently, many stores are refusing to sell Spirit Tracks on its release date, with such reasoning as “because most games come out on Tuesdays”, even though they already have the game in stock.
Before you ask, the given release date of the 7th is perfectly correct. Even the official Spirit Tracks site claims the release date as the 7th, as do all of the promotional posters for the game that you will find at the shops themselves.
Unfortunately, some major chains are simply refusing to sell it, due to (what appears so far to be) some sort of twisted form of videogame bureaucracy, so if those stores are your only options, you may just have to wait another day.