I was trying to use two regular pistons and a switch with a redstone torch to shift a block back and forth as a way to switch tracks that are parallel to each other. I used two pistons set two blocks apart, one lever, one redstone torch, and two lines of redstone wire (4 blocks long each). Without pulling the lever, one piston is extended and the other is at resting position.

What I expected to happen was...:
With this setup, without the block between the pistons, as the lever is pulled, the piston on the left will extend and the piston on the right will retract. I expected the same to be true when you add a block to the one block space that is always between the two pistons.

What actually happened was...:
When the block is placed in front of the left piston (with it being retracted), the block stays still, and the right piston retracts (both pistons retracted). When the block is placed in front of the right piston (with it being retracted), the left piston retracts, the right piston extends, and the block moves, but when the lever is then pulled again, the first scenario happens.

Steps to Reproduce:
1. See attached photos
2. Note: If scenario two is attempted first, and the lever is pulled repeatedly, the block will sometimes move to the left and back again, but only occasionally.
3. ...