Rail

Minecart Tracks (or Rails) are, as suggested, tracks where Minecarts easily roll across. Minecart tracks change when placed specially. The track forms corners where two perpendicular tracks meet, and if there is a one-block height difference between two sections of track and room behind it, the lower section will turn into a ramp. Tracks will be destroyed if they are touched by lava or water, similar to torches. Trees growing over tracks will destroy them as well. Although there are no cross-section tracks, you can use a lever to switch track directions in corners, allowing multiple paths for your track.