The origin of "Mahler Grooves"

Growing up in Washington DC, I rode a school bus that passed the intersection of Canal Road and Arizona Avenue, where an old railroad bridge crosses overhead. For much of the nineteen-seventies the bridge support was emblazoned with the legend MAHLER GROOVES, next to a painting of a French horn. I recounted this story in a New Yorker article in 1995, and received a lovely note from Dr. Stephen Chanock, of the National Cancer Institute, who corrected my account (I had remembered it as "Mahler Li