The Main Features.

These consist of (1) A reliable power supply of alternating current throughout the system.

(2) A continuous series of electrified bonded tracks insulated from each other.

(3) Signals electrically operated, and controlled by those tracks and situated at appropriate intervals.

(4) The necessary instruments and devices to operate and co-relate these signals to their controlling track and to one another.

(5) Shelters to house these instruments and connections.

(6) Connecting wires to join up all the various units detailed above into a continuous system.