When riding on minecarts, when your minecart moves a block, it sounds as if you were running at a fast pace. It sounds like you're walking on whatever block the minecart is on.
MCPE-28942
Walking Minecart
Resolved
Fixed
2
Started to notice this in 1.2.5. The cart also appear to move slower.
Sometime, my Hopper minecarts will freeze in the middle of a circuit with more than enough powered rails to normally make it loop the circuit.