Final answer:
The 1941 song about a fictitious train through Tennessee that was the first song to receive a gold record is "Chattanooga Choo Choo."
Step-by-step explanation:
The 1941 song about a fictitious train through Tennessee that was the first song to receive a gold record, selling 1.2 million copies, is "Chattanooga Choo Choo." It was recorded by Glenn Miller and His Orchestra, with vocals by Tex Beneke and the Modernaires. This popular big band swing song was featured in the movie "Sun Valley Serenade." The phrase "Chattanooga Choo Choo" refers to the Chattanooga, Tennessee, train station.