This same game has been sold in three different levels of packaging and components. See http://boardgamegeek.com/thread/163281
There have been three editions, one of which is no longer produced
What we might call the "Original" Edition was in a wooden box that folded out to reveal the playing board on its inside surface. This edition had metal cars and tin sheets printed for resource tracking. It did not have the custom cards now found in Bookshelf and Discovery editions. It is no longer produced.
The Bookshelf Edition is also a wooden case, but the case has a book-shaped construction. It has metal cars. The playing board is a standard game construction.
The Discovery Edition is a cardboard box. Cars are plastic. Standard game board construction.
The Bookshelf Edition and the Discovery Edition share the instrument panel-shaped accessory for resource tracking, which is considerably different from the accessory used for this purpose in the Original Edition.
I am told the graphics on the playing boards are slightly different for Bookshelf and Discovery. I might suspect this means the pictures in the corners, but I cannot see a difference on the publisher's web site. There should be no difference in the track layout.