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> the attackers had started fires in "conduits carrying multiple (fibre-optic) cables" that relay "safety information for drivers" or control the motors for poi

> the attackers had started fires in "conduits carrying multiple (fibre-optic) cables" that relay "safety information for drivers" or control the motors for points that change rails... Farandou of SNCF said: "There's a huge number of bundled cables. We have to repair them one by one, it's a manual operation" requiring "hundreds of workers". Just wondering: is there a reason why there needs to be a bundle of fiber optic cables to carry safety information and control the rails? Is that not overkill? I assume wireless/cellular networking is not robust enough, but what just standard-ass copper wires, like the telephone lines? I assume the reason is that they're transmitting more than just what was named in the article, but all I know is what I read.

eaglefield 2y ago
Could be that fiber doesn't have any resale value. Whereas copper theft is a somewhat common issue.
bboygravity 2y ago
Sometimes fibre optic cables are used for reasons other than lots of bandwidth in architectures other than network A to network B. Examples: 1. transferring data near/from/to high voltage lines, without risking short circuits that cause fire/death/damage (personal experience: getting info in/out of particle accelerators that hold mega volts of tension) 2. using fibre optic cables to measure vibration or deformations (using the fibre as sensor) 3. physical layer redudancy in case of failure 4. keeping safety critical systems physically seperate from other data transfers There are probably more reasons that are possibly more on-topic. I'm definitely not a fiber applications expert.
supertrope 2y ago
Copper is distance limited. Copper oxidizes. If you are ever going to have any data transfer copper requires powered equipment at very close intervals. Metallic cabling and any equipment on the ends is vulnerable to nearby lightning.
15155 2y ago
Electrical signaling runs into ground potential differences over long distances, fiber does not - each node is optically isolated.

eaglefield 2y ago

Could be that fiber doesn't have any resale value. Whereas copper theft is a somewhat common issue.

bboygravity 2y ago

Sometimes fibre optic cables are used for reasons other than lots of bandwidth in architectures other than network A to network B. Examples: 1. transferring data near/from/to high voltage lines, without risking short circuits that cause fire/death/damage (personal experience: getting info in/out of particle accelerators that hold mega volts of tension) 2. using fibre optic cables to measure vibration or deformations (using the fibre as sensor) 3. physical layer redudancy in case of failure 4. keeping safety critical systems physically seperate from other data transfers There are probably more reasons that are possibly more on-topic. I'm definitely not a fiber applications expert.

supertrope 2y ago

Copper is distance limited. Copper oxidizes. If you are ever going to have any data transfer copper requires powered equipment at very close intervals. Metallic cabling and any equipment on the ends is vulnerable to nearby lightning.

15155 2y ago

Electrical signaling runs into ground potential differences over long distances, fiber does not - each node is optically isolated.