1971 Sears Wish Book page 148...I believe this is the page that caused the confusion in Greenberg's Guide to Lionel 1970-1988. Everything else on the catalog page is Lionel, so the Greenberg writer assumed that the Speedrail set was Lionel also. It's not...Sears just happened to have space on that page for it. As franktrain's reply shows, it was offered again in 1972 (but not surrounded by Lionel product this time).
I've read the 1970-1988 Greenberg book, and I have Greenberg's Guide to Lionel 1970-1991 Volume 2 (which has a section on department store sets)...I remember the Greenberg mention of the Speedrail set, but it isn't in the 1970-1991 edition, so it must have only been in the 1970-1988 one.