Minecarts Not Moving Properly

The minecarts I placed are not working properly and even flying off the tracks and then returning to the tracks again.
What I expected to happen was...:
The minecarts would move back and forth on the tracks and cluster together.

What actually happened was...:
Some of them went inside each other but then stopped in the middle of the track and the other minecarts stopped working also. Video and World Save of this glitch: https://doubleteammc.wordpress.com/2015/12/03/new-minecart-glitch-1-8-8/

Steps to Reproduce:
1. I am not exactly sure but it was on a slant and I placed like 20 minecarts
2. Then I accidentally got in one of them and all the minecarts stopped in between two tracks starting to slant.
3. Then when I placed more on top of the hill leading to the stuck minecarts and those aslo quit working.