For a fun little sandbox experience,
Train Frontier Express could be exactly what you desire.
INDIEGAMES.COM

A remarkably fully featured offering.
EUROGAMER

A nice break from all the side-scrolling Indie games.
KOTAKU XBLIG Pick

WINNER 2011
Indie Games Summer Uprising

Blazblue.centralfiction.part1.rar -

You can BUILD, RIDE, SHARE with friends in a this landscape building and rail riding good time.

Sculpt your own landscapes, then HOP ONLINE to share your map, take a ride, or build together in REALTIME.

Train Frontier is both STYLIZED and FRIENDLY, taking inspiration from MODEL TRAIN SETS, while eschewing the more complex train sim format.

Blazblue.centralfiction.part1.rar -

Includes a 40+ hour Story Mode, Arcade Mode, and various "Grim of Abyss" RPG-lite modes. How to use this file

All parts must have the exact same name, differing only by the "part#" suffix. BlazBlue.Centralfiction.part1.rar

Released by Aksys Games and developed by Arc System Works, Central Fiction is the final chapter of the "Calamity Trigger" saga. It is a high-speed, 2D anime fighting game known for its deep technical mechanics and massive visual novel-style story mode. Key Features Includes a 40+ hour Story Mode, Arcade Mode,

Provides the definitive end to the "Azure" storyline that began in 2008. Includes a 40+ hour Story Mode