American Flyer train #290 steam engine an tender

This is an American Flyer # 290 steam engine an tender! I dont know much about trains hopefully the pics will tell the story The wheels all move with ease, BY turning the motor, I see no broken parts There is a little switch on the bottom of the tender But i dont know what its for! If ya have any ? just ask thanks for looking. Ps its Quite dirty did not want to clean leave that up to you , I know from experiance not to clean vintage stuff !