It is interesting to note that there once were no less than four streetcar lines on 125th Street: K, Broadway-Kingsbridge; T, Third and Amsterdam Avenues; W, Willis Avenue; and X, 125th Street Crosstown. The K was motorized on June 22 1947, the T on May 18 1947, the W on August 5 1941, and the X on June 29 1947.
The Mack C-45 buses in this photo are probably on the M100, Broadway-Kingsbridge and M101, Third and Amsterdam Avenues routes, for BX29, Willis Avenue was served by prewar Macks until well into the 1950s. The M102, 125th Street Crosstown bus line was dropped only two days after it replaced the streetcars.
Caption data from Bill Armstrong; photo courtesy the Bill Volkmer collection