Press "1" to make the train track left-leaning only. Press "2" to make the train track right-leaning only. Press "0" to make the train track lean on both sides. Press "A" for normal train track. Press "S" for the green ball; using this ball on a track makes it the starting track. Press "D" for the deleting ball; will delete anything when clicked. Use left/right arrows to turn the track pieces. Press Space to start the train.