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?

Maybe you are the kind of person who would fit a complex, unknown system
to a train saying `Its the latest hi-tech system`, it is what you need,
string is so 18th century?

If a piece of string works, then what is the problem?


You could put in electronics, a button, introduce a software controlled
system and a processor.

The simple fact is that the mechanical properties of a piece of string
have been understood for centuries.

(although, according to another thread, this still means people are
silly enough to buy the wrong sized string )

Tim