If you use more than ten times minecart.The eleventh cart will disappear

If you use more than ten times minecart.The eleventh cart will disappear.
(P.S. It's like you are flying on the rail.Cool!)
And go on or under slope interface is "AWLSOME"!
Also if you are on the cart. It will never no power
I'm Chinese.I'm not good at English.
Hope you understand me.