When you place a minecart and pressing the "Ride" button the minecart will always disappear and you are standing beside the tracks.
My phone: Samsung Galaxy S4 mini
MCPE-10830
Minecarts disappear after clicking on "Ride"
Resolved
Duplicate
0
(Unassigned)
Unconfirmed
Phone - Android - Samsung Other (Specify in description)
Android 4.4.2
0.12.1
Retrieved
This is a known and confirmed bug. In the meantime, if you long press the "Ride" button you can get into the minecart.