Powered rails will only boost in one direction

If you place a powered rail, down and power it with redstone, and if you hop into a minecart, and if your facing north, and you go over the powered rail, you minecart will turn to the south and you will start moving south. if you are facing the south already, then the problem is fine. But please make it so that the powered rails can power you no matter what direction your going. Thanks! -MagicPopcorn