Minecart with Furnace

Powered Minecart
In Secret Friday Update 7, Notch implemented powered Minecarts. To create a powered Minecart you first need to have a Furnace and a Minecart, place the furnace above the Minecart in the crafting window, and you will obtain a powered Minecart. The Minecart can be powered only from coal.

To use the Powered Minecart, place it on a track, then select your fuel and right-click on the Minecart. When right-clicking on the Minecart, you want to face the direction you want it to travel. You can make the cart change direction by right-clicking it, facing the opposite direction of travel. No coal will be lost doing this. Destroying a Powered Minecart will give you a Furnace and a regular Minecart.

Alternatively, going up at a slope of 1/3 (two flat-rails between each up-ramp) will allow you to push your train upwards, as it appears the powered minecarts have force applied in intervals.

Important Notes

 * A player inside adds significant weight to the cart, making it harder to push
 * Breaking a "special" cart gives a plain cart and the chest/furnace back (but not fuel)
 * Multiple powered minecarts are able to add additional power to the train, 2 powered minecarts can push your minecart up a 1/1 slope although very slowly.
 * A Single powered minecart can push your minecart up a 1/1 slope if there is one or more other minecarts also being pushed along with yours.
 * Powered minecarts cannot push others around 180-degree hairpin turns
 * 1/1 (and possibly 1/2) slopes cannot push players up. 1/3 slopes appear to be capable of this.