In 1970, the FCC forced Triangle to sell off its broadcasting properties due to protests from then-Pennsylvania Governor Milton Shapp.
WFIL radio had been an ABC radio affiliate dating back to the network's existence as the NBC Blue Network.
On March 26, 1948, it aired a production of "Parsifal" from the John Wanamaker Store that featured Bruno Walter conducting 50 players from the Philadelphia Orchestra, a chorus of 300, and the Wanamaker Organ.
Perhaps its most notable local production was Bandstand, which began in 1952 and originated from WFIL-TV's newly constructed Studio B (located in the 1952 addition to the 46th and Market studio).
With the anticipated arrival of WFIL-TV, Triangle secured a new facility for the stations, located at Market and 46th streets, which opened in 1947.
In 1963, Triangle built one of the most advanced broadcast centers in the nation on City (or City Line) Avenue in the Wynnefield Heights community, in a circular building across from rival WCAU-TV (channel 10).In the FCC's view, the merger gave the new company a de facto duopoly prohibited by the regulations of the time—the same "one-to-a-market" rule that forced Triangle to split its newspaper/broadcast combination in Philadelphia many years earlier.