A family of rail-building games where players draw track on the board, use that track to fulfill delivery orders, and use the money they earn to expand their rail system. Games include Empire Builder, EuroRails, Iron Dragon, and several more.
Many of the games are based on real geography -- Empire Builder for the US (later augmented by North American Rails), EuroRails for Europe, Nippon Rails, India Rails, etc. Two are extra-terrestrial and expeculative, Lunar Rails and Mars Rails; these add the idea of a "3D" map (disks with connection points along their edges). Iron Dragon is set in a fantasy land and adds the concept of train "foremen" who give different abilities.