Joe O,
What is the "10/96 PC version" of Chattanooga Choo Choo?

The only part of the original lyric I can see some people might find non-PC is the use of the word "boy." But since the lyric doesn't specify the age of the guy being addressed, there's no reason to assume he wasn't indeed a kid.

As for the Chattanooga Shoeshine Boy song, yeah, it's likely it was about an adult male of African descent and if that's the case, calling him "boy" would be demeaning and thus non-PC. But even in that song, we don't know that the "shoeshine boy" wasn't 10 or 12 years old or a teenager.