The south-west rule is a tricky glitch present in Minecraft that disallows the crafting of certain rail structures if those structures are facing a certain direction. If you want to know more what the south-west rule is, take a look here-
However, I've recently found a simple way to build compact flat resets for minecart boosters regardless of the direction they face. And when I say simple, I mean simple. Just use a redstone torch at the side of the circular track. The circuit will turn the track into the desired shape, and then you can pick the redstone torch back up and go about your day. Here's what you can manage using this exploit. The things in the image may seem mundane to a beginner, but more experienced crafters will definitely recognize the significance.
Here's a rundown on how to do this:
1. Build your reset as you would normally.
To do this, you place one rail track on each block of a 2x2 space. When done, the rails should meld into a circle.
|Step 1: Make a circle|
Then lay a straight rail track leading to the 2x2 circular rail track.
|Step 2: Make a straight track|
After that, remove the track piece from the circular track where the straight track touches the circular track.
|Step 3: Remove this piece...|
Finally, replace the piece you just removed. After doing so, one of two things will occur: Either the track will again become circular, which will mean you will need to use the bypass, or the track will turn into a hook shaped reset and you need not do any more work.
If, however, it turns into a circle again, then your track is either facing the south or the west.
Well, in that case .....
|Failure! On to the bypass!|
2. Place a redstone torch on the block next to the circular rail track where the circle track and the straight track meet. Make sure the torch is adjacent to the circular track, not the straight track. The track should turn into the desired hook shape.
|Put a torch!|
3. Remove the redstone torch and go make yourself a samdwich. You're done here.
The desired result...