The Pan American - L & N Railroad

The Pan-American was a passenger train operated by the Louisville and Nashville Railroad (L&N) between Cincinnati, Ohio and New Orleans, Louisiana. It operated from 1921 until 1971. From 1921 to 1965 a section served Memphis, Tennessee via Bowling Green, Kentucky. The Pan-American was the L&N's flagship train until the introduction of the Humming Bird in 1946. Its name honored the substantial traffic the L&N carried to and from the seaports on the Gulf of Mexico. The Pan-American was one of many trains discontinued when Amtrak began operations in 1971.

Source

Postcard of the Pan-American as it passed the WSM transmitter in Nashville.

Another source with additional information and some more photos of different EMD locomotives used is at American-Rails

"The Pan-American" (1948) by Hank Williams

This song is one in the playlist from a previous post and was the reason for this post. 

More information on the WSM transmitter tower found at Wikipedia. I have seen it numerous times.

WSM's unusual diamond-shaped antenna (manufactured by Blaw-Knox) is visible from Interstate 65 just south of Nashville (in Brentwood) and is one of the area's landmarks. It is located near the I-65 exit 71 interchange with Concord Road (State Highway 253). When the 878-foot tower was built in 1932, it was the tallest antenna in North America. Its height was reduced to 808 feet (246 m) in 1939 when it was discovered that the taller tower was causing self-cancellation in the "fringe" areas of reception of the station (it is now known that 195 electrical degrees, about 810 feet, is the optimum height for a Class A station on that frequency). For a period during World War II it was designated to provide transmissions to submarines in the event that ship-to-shore communications were lost. It is now one of the oldest operating broadcast towers in the United States.
As a tribute to the station's centrality in country music history, the diamond antenna design was incorporated into the new Country Music Hall of Fame and Museum's design in 2001. The tower is listed as a National Engineering Landmark and was listed on the National Register of Historic Places on March 15, 2011.