en 1.8 /summon Mechanismus Basicly  when you power the command block it will make a computer jump in and on the first command block in there a redstone block.Before that you will set your world spawn 5 blocks away from the computer then do what I done.Suffer in the redstone block then after that go and go in creative and get 10 diamonds a one spawn egg villager.Spawn the villager and drop the diamond just under him.He should translate into Trayarus.Then enter is interface and put your 9 diamonds in his interface and then you'll get the diamond minecart.Spawn it and there you have it look where you want to go and it'll go in that direction.Good luck :)