On 13 Oct 2005 06:16:55 -0700, "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?

What would you prefer? A switch, a relay, an actuator and a bit of
wire? Why be complicated if a simple mechanism works?