You drive a train that transports coal. You can choose between three different trains: one's faster, one has a better balance and one's accelerating faster. Once you've completed all the levels, you can also drive the supertrain, that combines the best of all three other trains. If an exclamation mark appears, you'll have to slow down. Collect all yellow icons, that represent achievements. In the shop you can upgrade your train with the money that you've earned. Drive the train and keep from spilling too much cargo. Upgrade train as you unlock new maps.
Instructions: Instructions are in the game