Engine Modules

Engines are modules in Steve's Carts that power minecarts.

Coal
If a minecart is mining coal, it will refill its fuel slot with coal if there is space available.

Solar
The solar engine can only run during the day with a clear view of the sky, but it will continue running when it's raining. At other times, such as at night or underground, the minecart will need the coal engine as a power source.