In article ,
Paul Corfield wrote:
Another blockade that springs to mind is the Waterloo and City Line -
twice. Once to get the 92 stock in and working I think - there was the
800 replacement bus service and then, of course, much more recently to
do the track and signalling works and to refresh the trains.

Entirely off topic, but how come it was called no. 800? According to
Wikipedia, TfL don't use numbers 700-899 for bus routes to avoid
clashing with long distance coaches. Any idea why this service was an
exception? -- or did that rule not exist back then?

-roy