If you were in a government Cyber-warning center

Unnamed Administration sources reported that Chris Kilbourn said:

In the past few years on NANOG, I've noticed a strong correlation between
train derailments and network outages. (Not to discount the backhoe
correlation in any way of course...)

The question I have is this:

If fiber runs are trenched into the railbed, and we know that trains
go off of the tracks every now and then, what, if anything, is being
done to harden the conduit?

Conduit? What's THAT ;-? Only exposed (bridge crossing, etc)
parts are in conduit.

Would trenching it deeper help? Has encasing the conduit in a
steel-reinforced channel been examined? Or is there something about
laying conduit next to track and the accident modalities that I am
just missing here?

A) There's limited right-of-way. Who are you already next to?
ATT? MCI? Sprint?

B) There's limited ACCESS to A). You either must shutdown the
rail line or follow a rigorous safety program to ensure you don't
have a piece of whatever sticking out across the track when that
train goes by.

C) How deep do you want it? ATT put their #5 TCC cable down 4';
no easy task. {But then, we paid for it...}. Will that help
when a locomotive lands on it? If it doesn't... it's much harder
to fix.

D) There's limited money.

The average locomotive is something above 100 tons. On anything but your
usual passenger service, it's common to see at least 2, and up to 4, units
on the front (often not all of them are in service or at full capacity).

It's also relatively boxy, nearly flat. Flip it over, cause the front bit
to go do into the dirt, and it will make a *lovely* plow. Anyone doubting
this should look at aerial footage from news crews after such an accident;
things often look like a road-scraper went by.

4' might be deep enough - and it might not, though I'd suspect that it will
be protected from most derailments. But, as noted above... 4' costs a lot
to accomplish.

If the cost of a derailment-induced outage is low (latency, rerouting, a
few minutes of problems while the system reacts), it probably costs a hell
of a lot less than burying that many miles of cable 4' deep. Even when you
run the averages. And 1' deep probably just isn't going to cut it, as it

You can also add to that:
If the original derailment didn't cut the cable, the subsequent construction surely would.
The cable buried is an afterthought, rail repair crews will undoubtedly bulldoze things flat and straight, bring in fill and push the debris to one side, and get the ballast and rails back in, tamped, and service restored as quickly as possible. Over a period of time, after, they will remove and scrap, all with big machinery, shipping the repairable to a rebuilder...your glass cable doesn't mean an iota to the rail company when they need to restore service and get the right-of-way open. An outage of this nature on a main track may take days to a month or so to be ready for a crew to re-install the glass, splice and restore that path.

Needless to say, this is what redundancy is all about...