Unreal fortress evolution is the Official version of fortress only for unreal tournament 2004, team fortress started way back for quake and has graced every major engine and its update since then, every version has tried new things and have adhered to the engine.
Nice mod on the principle, but it's not as good as the UT99 version of the fortress mods (Unreal Fortress, Weapons factory) it still entertaining and fun to play.