You know how sometimes you accidentally send a minecart shooting out down your tracks, and you can only watch helplessly as it fades into the distance? And then you know that you have to go find it and break it, so that it doesn't stop up your cart traffic on your tracks.
Well, no more!
For a long time, there have been cart return systems that would send an unoccupied minecart back to the beginning of your track, but they were always a little more complicated than necessary.
Now, using tripwires, you can make the simplest cart return ever. It uses one tripwire and four bits of redstone. That's it! Here's a video of it in action:
As you saw in the video, this is extremely simple.
You begin with a starting point, which can be any kind of design you prefer. In this case, I've chosen a unique 1.3 design, which uses no special starting point whatsoever. Instead, it takes advantage of a new feature of Minecraft 1.3, which is that you can move minecarts very slowly by pressing the forward key while sitting in them.
The next bit is really easy: just make a loop of track. Make sure it connects back to your starting area.
I recommend leaving one piece of unpowered rail as your starting point, because one unpowered rail is enough to stop an empty minecart in its tracks, no pun intended.
The last piece of the puzzle is the actual mechanism involved.
The first thing you need is a tripwire that's suspended one block up in the air. This way, it will trip only when someone is riding it, and not otherwise. Make sure that you do one of two things, though:
- Put the tripwire directly next to the place you want to switch rails, or
- Use a pulse sustainer to lengthen the signal.
Other than that, all you have to do is run some redstone to the intersection you want switched. When you provide power to a T-intersection, it will swap the connection. That's really all there is to it!
It's such an incredibly simple design, but it's extremely useful. I recommend building one of these onto every track you make, especially on multiplayer servers. You never know when people will shoot off carts for no reason. You can even have multiple cart returns placed periodically along your track, just in case someone decides to bail midway through your ride.
If you have any difficulty with this, make sure you watch the video! You can also see me get angry at slimes, which might be worth it all on its own.