I haven’t had the opportunity to ask the folks at Maxis what motivated them to make this game the way they did, but it wouldn’t surprise me if it was simply because they either.
The puzzles themselves are fascinating, Rube Goldberg-ish style games. Different-colored marbles are dropped into funnels and wend their way through various bits of machinery.
Along the same lines as SimCity and Railroad Tycoon, A-Train allows you, the city's leader, to layout, design and build a civilization of your choice and manage its resources.