"On The Atchison, Topeka, & Santa Fe" is not only a highlight but a milstone in movie musicals. The number runs nine minutes and takes in the entire cast and a vast amount of scenery. growing from the expectation of the train's arrival to a full glorification of its being.

This song was Harry Warren's last of three Oscars and lyricist Johnny Mercer's first of four. It was also Harry Warren's third great movie train song, after 42nd Street's "Shuffle Off To Buffalo" and Sun Valley Serenade's "Chattanooga Choo Choo." Warren came up with the most singable melody conceivable and Mercer exhausted his fertile mind, reeling off chorus after chorus of brilliant rhymes (hardly repeating a line) - enough to fill nearly nine minutes of screen time with constant singing. Metro recruited virtually every studio singer in Los Angeles for the soundtrack session, including members of two groups, The Music Maids and Jud Conlon's Rhythmaires, who worked regularly on the Bing Crosby radio show.

This Song spent 8 weeks at the top of the charts in 1945.