Minecart Rail Basics: The South-West Rule

An important part of understanding minecarts in Minecraft lies in knowing the south-west rule. Not knowing the rule can cause a crafter a lot of grief as he or she tries to figure out why a minecart at an intersection only travels to the left or right, or why a booster resetter seems to only work when facing one direction. The south-west glitch of minecarts comes from the fact that blocks essentially "begin" at their north-east corner, which somehow lends many blocks different properties depending on the direction they are facing.

The south-west rule of minecarts states that minecarts will favor the south or the west direction when meeting at an intersection and the north or east direction when joining tracks. This means that when a minecart travels to a T-shaped intersection, it will travel either to the west or the south, and that when a booster resetter is made, the hooked end must face either the north or the east (unless you use the bypass I spoke of in previous posts.

Here are a few example of the south west rule in action on intersections:

Notice how one track overlaps another? If the track on top runs east to west...

...your cart will travel west!

If track on top runs north to south...

...then your cart will run south!

Note that the track on top decides which way the minecart will turn at an intersection.

And here is an example of the north-east rule in action on hooked resetters:

Only the resetters facing north and east are working at first...

But of course, the hooked resetter can be fixed easily as described earlier.

...but with some redstone torches, that's not a problem!