The second, actually. The first was considered such a one off they
thought it would never happen again, only to be proved wrong 11 years
later. Then the plan to install speed controlled trainstops in tunnel
sidings started, only to be extended to outdoor sidings after an
accident in Rayners Lane siding in 1972. Of course, no-one ever
thought a driver would fail to stop in a terminal platform, yet thirty
years ago today the unthinkable did happen.