It is a game that guides the locomotive to the goal by operating the points on the track.
Touch the track to change the direction.
The locomotive runs on coal, so it will stop when the coal runs out.
Since coal is falling along the way, if it seems that you will run out, lets supply it even in a detour.
Also, the gate is closed just before the goal, so lets go through the key and open the gate.
Grades are determined by the elapsed time to the goal.