I switched to snapshot and i noticed that i can't no longer press ,,W" to go forward with minecart. So you can't no longer press W to start going , that means you can't start going on powered rails if you have mix of normal and powered rails you need to make a ramp bit more powered rails button but it is annoying. Idk if its a bug or it was changed like this. I am thinking it is a bug.
Have a nice day