When I'm using a minecart, it doesn't go back and forth and eventually it just stops even though there are power rails. Also when You push the minecart on a activated power rail it stays the same speed as the normal rails. 

When I try and get into the minecart it kicks me out instantly when it touches a powered rail. If the minecart stays on top of a powered rail, it goes left and right continuously which means you can't hop in and if you get in it kicks you out straight away.

im playing on Minecaft Bedrock Edition