I don't think this track-building tour de force has been posted here before. Seems it was begun by the UK's Chris Frost in 2009 and has been updated as recently as this year. I don't know anywhere else where this level of experience, knowledge, and detail can be found.
Chris's intro:
"The techniques for building slot car tracks are much the same for any layout - be it a two-lane track in your loft, a Slotstox oval track, a four-lane club circuit, or an eight-lane mega-track. Many of these web pages are based on my articles published in Slot Car Racing News, although I've added a number of new topics since.
These pages include what I've learned from building six club tracks over the years, helping maintain all the various National Championship tracks since 1972 and all three of the tracks used for World Championships in the UK, and from talking to lots of other people (from professional builders to people who have built one club track). That certainly doesn't mean I know all the answers - you always learn something new when working on tracks...
Thank you to all the people who have contributed information to the site."
Building and Maintaining Slot Car Tracks
(There's a detailed table of contents on the link's first page.)