Powered rail duplication

This is not the exact same setup, but I guess that it is related to the bug that is marked as "Fixed" in this https://bugs.mojang.com/browse/MC-6903

The bug is on youtube here:
https://www.youtube.com/watch?v=AoPRufK8r0k&index
and here:
https://www.youtube.com/watch?v=m1BTa8TMQYQ&index=15&list=WL

And I could reproduce it quite easy in both 1.7.10 on a multiplayerserver in survival and in the snapshot 14w31a.

It works with any of the "special" rails in the game.