3 ms·

Anecdote time: I was in a train that hit a bunch of concrete slabs at medium speed (60 km/h?) and all I noticed was that it rapidly stopped. But that was a rel

Anecdote time: I was in a train that hit a bunch of concrete slabs at medium speed (60 km/h?) and all I noticed was that it rapidly stopped. But that was a relatively undetermined attack. What if someone welds something directly on to the rails or cuts something out? It may get noticed in tens of minutes, but is that really fast enough? Similarly it seems like it wouldn't be insanely hard to poison water supplies, doing some damage before it gets shut off or destroy other bits of infrastructure (I hear it has been tried with the electricity grid). Society is a fairly complex machine and I'm surprised how well it works.

sudosysgen 6y ago
Cutting out the rail is unlikely to cause huge damage, and welding something directly to the rail would take quite some time and be noticeable. Just putting a few sensors every few meters and networking them then stopping the train would work. But I am also surprised how well it works. I think people just don't suck as much as one would expect.
- jimktrains2 6y ago
  Cutting the rail would also break the track circuit and force signals to red.
- Xylakant 6y ago
  > A few sensors every few meters. The US has a total length of about 300 000km of railway network and that probably counts multi-track connections once. And it doesn’t include subway or anything. So that would be a lot of sensors that need to be placed and maintained. And you’d need to except some failure of sensors, so you cannot just stop if a single sensor goes haywire. It’s certainly not impossible, but also not trivially done.
Mountain_Skies 6y ago
Years ago I knew someone who worked for the local waterworks and asked what they do to prevent the water supply from being poisoned. He said while they do test on a regular basis, the real security is in the dilution factor as you'd need a really large quantity of any poison to effectively contaminate a reservoir. A biological contaminate that reproduces would be an easier attack but I'm guessing that's where the frequent testing comes in to catch it before it gets to a deadly concentration.

sudosysgen 6y ago

Cutting out the rail is unlikely to cause huge damage, and welding something directly to the rail would take quite some time and be noticeable. Just putting a few sensors every few meters and networking them then stopping the train would work. But I am also surprised how well it works. I think people just don't suck as much as one would expect.

jimktrains2 6y ago
Cutting the rail would also break the track circuit and force signals to red.
Xylakant 6y ago
> A few sensors every few meters. The US has a total length of about 300 000km of railway network and that probably counts multi-track connections once. And it doesn’t include subway or anything. So that would be a lot of sensors that need to be placed and maintained. And you’d need to except some failure of sensors, so you cannot just stop if a single sensor goes haywire. It’s certainly not impossible, but also not trivially done.

Mountain_Skies 6y ago

Years ago I knew someone who worked for the local waterworks and asked what they do to prevent the water supply from being poisoned. He said while they do test on a regular basis, the real security is in the dilution factor as you'd need a really large quantity of any poison to effectively contaminate a reservoir. A biological contaminate that reproduces would be an easier attack but I'm guessing that's where the frequent testing comes in to catch it before it gets to a deadly concentration.