Copper Rails

I just had an idea for copper rails. This would solve two problems with one block (Minecarts being too slow and little use for copper). These rails would make the minecarts move 25 blocks a second compared to the 8 blocks a second the vanilla minecart moves. However what would balance this is if you were going fast enough your minecart would de-rail if the rails change direction. This would give an alternative to the Elytra and make minecarts useful again, without affecting current minecart setups like rollercoasters and various farms. Aswell as boosting the usefulness of copper, which has little use late game.