This essay posted at mentalfloss.com isn't new, having been posted in March 2011, but it's still a pretty good piece that gets most of it right.
Little Engines That Could: A Brief History of Slot Cars
"For many kids growing up in the 1960s, slot cars were a regular part of Saturday afternoons. Even those who grew up after the little cars’ heyday have fond memories of the whirring sound echoing off the walls of a friend’s basement. Here’s a look back at these miniature racers that have entertained generations of drivers, both young and old."
Read the rest of the story HERE