ATCHISON, TOPEKA & SANTA FE Johnny Mercer didn’t come to New York recently on the Atchison Topeka & Santa Fe, but whatever he rode must have been going pretty fast because Johnny picked up some early speed that has spent him shooting to the celling of the entertainment world, his most immediate big splurge being on Your Hit Parade with Joan Edwards (Saturdays, CBS 9:00 P.M. EST). It was always in Johnny’s mind to be in the theater, but he was a wise young man and kept that to himself until it would do him some good. As a result, he submitted quietly to a formal education at the Woodbury Forest School in Virginia. His first acting was with an amateur group, the Savannah Players. In 1929, he landed a small part with the New York Theater Guild in its production of “The Hero.” His first song to capture the public’s fancy was “Out of Breath, Scared to Death of You,” which he wrote for the “Garrick Gaieties,” in collaboration with Everet Miller, who wrote the music.