Rail bug

Rail bug 1: When you retract a rail upwards by a sticky piston, instead of not retracted or breaks after retracted, the rail will be retracted and the rail still exist, even there is not blocks under the rail.
Rail bug 2: Extension of Rail bug 1, when you add a minecart on top of the rail, and retract it upwards using a sticky piston, the rail will retract upwards, and the minecart also, even there is no blocks under the rail (and the minecart).
Rail bug 3: Retract the rail upwards first as the steps of Rail bug 1. Then, extend the sticky piston again, the rail exist, but it also drops a rail item*.
Rail bug 4: Extension of Rail bug 2 and 3, simply place a minecart on top of the rail, then retract it by using a sticky piston, then re-extend again, and the minecart still exist.
*Rail bug 1 and 3 can allow players to create a rail generator. Please remove this weird, but awesome bug.
This bug actually occurs in 1.0.0 as I have updated my version now and tested it, and proof that the bug still exist.