This rule allows you to set a specific signal to automatic or an extended signal state. The signal must be named in order to select it from the list.
These signal states should only be presented to user-driven trains. AI drivers cannot understand extended signal states and will stop at the signal. Signal AI will treat the set signal as Danger, so the preceeding signal will show Caution. Care should be taken to reset signals to automatic after a train passes it, as this will not be done automatically.