Railway 32 is a program/screensaver for Windows which displays a side-on view of a rail scene. In its simplest modes, trains enter the scene at one side and travel across the screen; in more advanced scenes, they may perform more complicated movements.
The program is (almost) completely non-interactive; it reads its configuration from scene description files, and runs a scene (chosen at random or by the user) through its simulation until a timeout or the user chooses another. This may seem boring, but it's a great screensaver for anyone enthusiastic about trains; many users have been known to sit and watch the trains go by for hours.
The program is charityware; a small shareware fee goes to the author, Mark Goodspeed's, favorite charity.
The program comes with a small selection of built-in trains, all of British origin, but it is user extensible. A small but productive user community, centered around the Yahoo Groups mailing list has produced a wide range of add-on railway equipment and scenes. Recent versions of the program support packaged modules, enabling automated installation of third-party scenes complete with all their graphics files.