Activate Fleeting Button
Fleeting a signal allows it to automatically set a route when a train approaches.
Enabling a fleetable signal is done using the Activate Fleet Button, together with the button of the signal. When fleeting is enabled, the "D" light beyond the signal is lit. When fleeting is disabled, the "0" light is lit.
Disabling a fleeted signal is done using the Deactivate Fleeting Button, together with the button of the signal.