Sun Valley Serenade

Sun Valley Serenade is a 1941 musical film starring Sonja Henie, John Payne, Glenn Miller, Milton Berle, and Lynn Bari. It features the Glenn Miller Orchestra as well as dancing by the Nicholas Brothers and Dorothy Dandridge, performing Chattanooga Choo Choo, which was nominated for an Academy Award for Best Song, was inducted into the Grammy Hall of Fame in 1996, and was awarded the first Gold Record for sales of 1.2 million.

Of particular note is the elaborate Chattanooga Choo Choo sequence. The scene begins at a rehearsal with the Glenn Miller Orchestra practicing Chattanooga Choo Choo and includes two choruses of the song whistled and sung by Tex Beneke in a musical exchange with The Modernaires. As the Miller band concludes their feature the camera pans left to reveal a railway station set. The band continues with the production number and accompanies Dorothy Dandridge and The Nicholas Brothers in their song and dance routine.Sun Valley Serenade is the first of the only two movies featuring The Glenn Miller Orchestra the other is 1942s Orchestra Wives. Besides Chattanooga Choo Choo, other Glenn Miller tunes in the film are Moonlight Serenade, It Happened in Sun Valley, I Know Why And So Do You, and In the Mood. ........

Source: Wikipedia