Several sheets of Spirit Tracks concept art, as well as art from various other games, were leaked by a Nintendo employee on 2chan and later posted by a user on the NeoGAF Forums. As you can see below, there are several different train designs and what even appears to be a flying boat-train! Seeing this makes me want Nintendo to release more Spirit Tracks artwork to the public.

Hit the jump to view a few pictures.

Leaked Concept Art

Leaked Concept Art