In Minecraft’s latest 1.5 update, you can now craft a Powered Rail, which will boost your minecart if the rail is powered, or stop it completely if the rail doesn’t have power to it.
To use this properly, you can place a type of switch at the ends of your track so that they’re off and will stop your cart until you want them to go, and place redstone torches next to your powered rail sections in the middle of your track so that they’ll automatically boost you without having to turn them on at every increment.
Each boost will only push your cart a certain number of blocks, so you’ll have to keep placing them in increments along your track, and going up hill takes even more powered rails.
To make a Powered Rail, you’ll need six Gold Ignot, one Stick, and one Redstone. Arrange them in your Crafting Table like the picture shows below to get your Powered Rail. You’ll get six pieces of Powered Rail every time.