We also had an AM simulcast here of Headline News on a couple stations. 910 AM (WTMZ) ran it for a little bit, along with 1450 AM WQNT, who did it for several years (starting around 2000 or so) They supplemented it with local simulcasts of the NBC's newscasts at 5 and 5:30.
St. Louis had the same. It was around 1993 when KUSA/550 dropped country for a Headline News simulcast. New owners changed the call letters back to KSD and Headline News was supplemented by local and NBC news simulcasts from KSDK-TV. Some talk shows were also sprinkled in before the format was scrapped in favor of standards.