This explanation (if current) explains the officers who provide CWTC.
City Wide Tour Commanders:
CWTCs on rotation 24 shifts. 3rd Alarms & discretion depending on injuries and other factors
C4A, 4B, 4C, 4D, 4E, 6, 7, 8, 9, 10, 11, 13, 13A, 13B, 15, 15A.
3rd Alarm will also get a Safety Command...