In the basement of the Community Center is the Overworld Train Station. There are multiple railways connecting to nearby player homes. Further points of interest will be connected via the Nether Train Station.
The current progress of the railways are as follows:
michaelericbrown: 100% complete
GhostFonz: 100% complete
Flutterbie: 100% complete
RBiblical: 100% complete
Taniquil: 90% complete
Visitors’ Duplex: 0% complete
TheDarkArcane: 100% complete
Quackzzz: 80% complete
The incomplete railways should be finished soon.
The current design allows for one cart per track, though a future design may feature multiple carts with switch tracks along each railway to always ensure there is a cart at both ends. (The Redstone Update, due in January or February 2013 will modify some of the track/cart behavior, so this redesign will await these changes.)
The large protrusion the player sees when he or she descends the staircase into this area actually conceals the wiring needed to allow the double doors to function upstairs.