It often gets as Lost in Translation as Bill Murray in a big, strange city. Also, it complicates many discussions between Swedes too because of the ambiguity and the fact that people seldom add qualifications to indicate which is intented.
Edit: Grammar.
Google can't really know which is which, so the article seems to use a mix of both english words in different places, which ends up being a little confusing/inconsistent.
Security is one of my interests and I work with people who have been in the safety industry, so sometimes we have our little linguistic bouts. :)
[1] http://www.nycsubway.org/wiki/Subway_Signals:_A_Complete_Gui...
A relay-based system like this might look simplistic and archaic to a casual observer but it's quite complex and there's no room for error. Formal proof (static analysis) is often used to verify both the formal specification that dictates what constitutes a safe system state, and the actual system's compliance with this specification.
There's a Swedish company called Prover specialized in this. I used to work there and moved to SF when we set up our US subsidiary.
The whole telephone network used to work this way, and actually many of those relays (and even the mounting frames) look identical to their telephone counterparts. And of course those were derived from the telegraph network, which is where all this stuff was invented. Send simple signals very long distances, very reliably.
As telephones got into automated switching with relay-based logic, complexity dictated that the systems be able to diagnose themselves to some degree. It's cost-effective for fully half the machine to simply monitor and isolate trouble in the other half, as that increases reliability and serviceability to the point where a large system can still work.
Even today with solid-state everything, the individual parts are more reliable than relays or vacuum tubes, but there are more of them, and there's always pressure to cut down on the manpower required to maintain the whole thing, so self-monitoring and fault tolerance is as important as ever.
Reliable system design is almost never synonymous with newest-and-fastest-and-smallest. It means well-understood technology with well-understood failure modes, airtight logic to control fail-over and fault isolation, and the hardiest components you can find for the given environment. In tunnels with cables running along electrified track, spanning city-scale distances with a whole power grid and weather and stuff happening in parallel, relays are still a sane choice.
If they call me, I promise they will get a new room for a pool table.
