Loc-O-Mania GBA is an excellent little puzzle GBA game developed by Michael EL-BAKI. It is designed as a puzzle game where you are displayed a land with different rail systems.
Trains will randomly appear in different stations located on the screen and must be guided safely to another train station. To do this you take control of the junctions on the railway, it is your decision on which direction to lead the trains.
While the game starts off relatively easy, you will have to quickly end up managing multiple trains at one time.