Basic Command Rules and Tips
It is important to be aware of these basic rules for action snap commands to work properly:
1. Action snap commands must always start with a white color (in the direction of train's movement). The white color alerts the smart engine to start reading a command right ahead. Note that there is one exception to this rule: it is the light blue color built into the switch tracks. Light blue is another special color that specifically alerts the engine about a track junction coming up right ahead. Because of this special meaning of the light blue color, there are no individual replaceable snaps made in this color.
2. You can make commands bidirectional by placing a white snap at both ends of the color sequence. This tip is especially practical for single-color commands (e.g. speed, stopping, reversing). This way the engine will read the command while approaching it from both sides of the track.
3. Do not leave gaps in color sequences. If you leave an empty slot after the white snap, the engine will see the black track and ignore the action color that may follow it. For the same reason, you will not be able to continue a command sequence across a track joint. So always assemble the whole color sequence on the same piece of the track.