Back in the early 40's, San Francisco's Market Street Railway discontinued its Castro Street cable car line, which terminated at 26th Street. I don't know how thorough they were about removing the tracks, but I do recall that a buddy of mine (who lived three doors down from 26th and Castro) was awakened one morning in about 1965 or so by vehement cursing in at least two languages. A work crew from the Water Department, excavating the intersection, had discovered the intact remains of the old turntable! Now that must have been a lot of fun to dig out after all those years . . .
Regards,
Paul