All sorts of transportation are very fragile. Everyone with a driver's license is trusted with operating tons of steel that can move at enormous speeds.
Society's based on some amount of mutual trust. We can't lock everything down and treat every person as a potential criminal. That leads to an inefficient and dystopian country.
If you have ever cycled on a national road, you know that this "mutual trust" fades away rather quickly in favor of "I can save 1 min and probably will avoid killing this guy if I accelerate right now".
Cyclists need not be involved. Just this morning on my way in to work I watched an SUV overtake me, decide they also needed to pass the guy in front of me, and accelerate up a hill in the wrong lane, not coming back into the correct lane until after cresting it. I later passed them as they waited to turn right at the next stoplight. People are just crazy stupid sometimes.
I mean, you're supposed to, and you'll get in trouble if you're caught driving without valid insurance. However, there isn't anything physically stopping people from driving irresponsibly.
On the contrary, you need to defend the entire length of the track at all times from an enemy who can destroy any small part of it at any time and then just leave the scene to try again later. Yes, it takes much more effort than a driver just deciding to go on a rampage, but against a determined adversary the train is at a huge disadvantage.
Derailing a train is an ordeal, though, and it's fairly easy to surveil against it. I'm fairly certain just blowing up the locomotive is less effort against modern networked rails.
Interference with railroad property, primarily oriented towards theft and even hijacking trains, was a very serious problem for much of railroad history. Ongoing issues with everything from train robberies to theft of the actual rails is what lead to major railroads forming some of the first nationwide law enforcement organizations. The FBI, for example, was directly modeled on the Union Pacific Railroad Police.
While train robberies are now decidedly rare, railroad police still exist today to patrol and protect the right-of-way, particularly in cities where theft, vandalism, and interference remains a real safety hazard. While less glamorous than train robbery, a common problem today is the theft of metal from signals, which disables the signals and creates a possible safety hazard.
A used rocket launcher was found next to the tracks for the transit system in Atlanta a few years back. Don't know if they ever found out how it got there but it certainly gave some uneasiness that there might be someone around looking to blow up passing passenger rail cars.
They make train de-railers specifically to protect work crews in rail yards. Someone who doesn't care about removing it later could just weld a similar shape (a slice of L channel would probably work in a pinch) to a track with some batteries. It should only take about 30sec if you walk up to the track ready to go.
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.
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.
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.
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.
OTOH the fragility of the original comment was about wilfully disrupting transports.
It's pretty easy to significantly distrust rail transportation. There are hundreds of rail suicides every year, and each and every time the line shuts down until everything's cleaned up. And of course you could destructively interfere with the train or railway, a rather common sabotage operation during WWII.
I can't seem to find a source, I heard about a culture (maybe Japanese?) where suicide by train is rare because of the inconvenience it causes others and the shame that brings your family.
When you go through the math on lost productivity due to train delays, you get some interesting conclusions. If a commuter train has 1,000 passengers making an average of $50 per hour who are, a delay is $833 per minute. That means it's more efficient (not going to touch on ethics or legality) to make minimal accommodations for disabled passengers and provide them point-to-point car service, instead.
According to wikipedia, suicide by train is common in Japan. In an effort to suppress this, life insurance policies often refuse to pay out for suicide by train and surviving family members may be fined.
Yes, a train engineer at the Port of Los Angeles intentionlly crashed his train in April because he was suspicious of the nearby Navy hospital ship Mercy.
'“You only get this chance once. The whole world is watching. I had to," Moreno told investigators, according to the complaint. "People don’t know what’s going on here. Now they will.”'
He must've been hoping the earth was flat enough that he could drive the train across water or something. Simultaneously amazing and terrifying that he could be put in charge of something so deadly despite what I'm sure is obvious mental instability.
Society's based on some amount of mutual trust. We can't lock everything down and treat every person as a potential criminal. That leads to an inefficient and dystopian country.