Neillw001 wrote:
Excuse my ignorance, but why in the 21st Century are saftey-critical
devices on one of the most heavily-used urban metro systems in the
World reliant on a bit of string?

If there was indeed a "bit of string" instead of a great thick rope, we
probably wouldn't have the current problem. We'd just have bits of
string breaking occasionally when drivers tried to reset the tripcock,
but that wouldn't affect safety.

--
Richard J.
(to e-mail me, swap uk and yon in address)