The Underground have long had backup safety procedures such as this in place
to work trains through sections safely in the event of signal failures. The
procedure described (trains travelling at very low speed until having passed
two known working signals) has been in place at least since the 1970s and

Well that certainly explains the delays. Is there any particular reason
for keeping
this absurd pantomime or is it just a case of the
thats-how-its-always-been-done
mentality?

B2003