I found when using powered rails I have a lot of glitching. Sometimes the display shows me flying off the track and into a group of blocks rendering me without vision and later returning me back into the mine cart further along. Also I find there is a significant increase in strength, where before i used 3 powered rails together between every 16 or so blocks, now I need one every 50 at most. If I use more than one per fifty I get another glitch with the mine cart as it speeds away at a constant speed for a random duration until it comes to an utter halt with no way of knowing when it will do so.