While riding in minecart,chunks beyond view distance chunks do not load as you move beyond the 16 chunks loaded. Initial speed is persistent all the way to the end of loaded area. Game freezes right before you reach unloaded chunks or you fly off the edge into the grayness, making minecarts unusable for travel across the map.
Possibly connected is horses can not be tamed, they do not buck you off and act as if they are tame without saddle. Unable to access horse inventory.
Effects Multiplayer and Single player.