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What we know so far about Spain train crash

https://www.bbc.com/news/articles/cm8xz7pkd0jjo
The following is hypothetical, since we do not have a proper safety report yet.

It sounds like the issue happened, because there was an error in the line-based train control system (LZB), which led to falling back to the point-based train control system (ASFA). However since there are more virtual blocks in LZB, than physical blocks in ASFA, this means that suddenly more than one train is in one block, which violates the most basic assumption of train control. That requires the trains to not rely on the train control at all, even if it says that the block is clear, but instead are operated manually.

I do not know what the proper procedures for that are in Spain, but in e.g. Germany that seems to require driving by sight. However that is also only after a number of accidents due this situation. So the following seem to be similar accidents from Germany:

- https://de.wikipedia.org/wiki/Eisenbahnunfall_von_Meerbusch-...

- On April 9, 2002, a near-collision occurred near Fallersleben. After a computer at the LZB control center in Fallersleben crashed, two trains on each of the two main tracks came to a stop. When the computer was restarted, the rear train in each pair was signaled a speed of 160 km/h, while the front train in each pair was signaled 0 km/h. One of the two train operators following saw the train stopped in front of him; the other, as a precaution, contacted the operations center, which warned him not to proceed.

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The level of human negligence here is astounding. The system did exactly what it was supposed to (lock the train down if the track can't be confirmed clear), and then a human controller ordered the crew to override the system, and ordered them to proceed at an unsafe speed towards a similarly disabled train?
Usually when you look deeper at failures like this, it’s because there’s a morass of bad incentives from the surrounding human system that enforces this kind of behavior.

Here is a plausible alternative explanation:

They’ve probably seen false warnings over and over and overridden them enough times that they lost sense of the risk. They need to keep trains on schedule, using a buggy system, with a manager looking over their shoulder. They override the warnings over and over, nothing goes wrong, and they forget that it may actually be right. Look at the Challenger explosion, Chernobyl, or any other failure like this, and there’s usually a bureaucratic process that has run amok, and the individual is just following perverse incentives that have been socially normalized over time.

So I’ll wait until I have more information before I proclaim this as human negligence and the system doing exactly what it’s supposed to do. We don’t know how often it was doing the wrong thing and confusing the fuck out of the human.

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Whose negligence, though? "The system" isn't just the LZB equipment - the train dispatcher is just another cog inside the same system, and should be expected to occasionally fail just like every mechanical part.

This isn't a game of Hot Potato where the last person touching it goes to jail for gross negligence. You have to look at it through a Swiss Cheese model: every individual safety layer can and will have holes, but a disaster can only occur when all of those holes align.

Why did the LZB system fail? Why did the train dispatcher use the wrong backup procedure? Why did a backup procedure with zero safety checks even exist? Why did the train operator accept this backup procedure? Why did the train allow high-speed driving under those unsafe conditions?

It does indeed seem like the train dispatcher made a big mistake, but that was far from the only thing that went wrong, and it would be myopic to use him as the scapegoat for a far larger systemic issue.

Overriding safety systems is itself a safety capability. But this wasn't a failure of the safety systems. It wasn't even a failure of the train drivers who had been over using safety system overrides. It was a management failure for not noticing that over use of overrides.
why does the dispatcher even hold the right to override the automatic system by themselves? this should involve multiple people, at least a signoff by a superior.
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Dispatcher, conductor at that time could not have know that dispatcher ordered manual bypass ignorig the rest of the guardrails of a traffic resume procedure
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{"deleted":true,"id":50299034,"parent":50287302,"time":1793326177,"type":"comment"}
Indeed the system is all of it - all gear on another level of abstraction where it as a whole is just enabling processes, not the thing running it.
If you ignore a road sign and run someone over in your car today, nobody will make systemic excuses for you.

Someone was driving the train who couldn't estimate the stopping distance relative to speed.

If a car is stalled in the middle of the road, and you hit it, that's on you. 200% if a reflective warning triangle was up 100 meters back.

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I would argue that we should look at systems-level explanations. The human factor is so glaring we can get caught up in it. There are what, 50?, high speed trains in movement in Spain at the same time. Even GPS + Starlink + 1 monitor (is that 50k€?) could have prevented this. But it happened, and the question is what is going on with train security in Spain in general for people to (be able to) make such decisions.
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The current control system dates from the early 90s. They started rolling a modern system with more redundancies and automatic blocking in 2022 but it's still not fully deployed.
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oh man, the override thing is super dangerous. I use FSD in Tesla a lot and there is a lot of times I "override" with the gas pedal because I think it phantom breaks or being slow and there were at least 2 cases where there was legitimate reason to stop (person crossing in my blind spot).
They have a failsafe to use (visual) block backup signaling on that line and used it incorrectly. 200km/h is right at the border where you don’t need in cabin signaling.
Too bad they don't run it with AI. Then it would be nobodies fault!
Sorry, but ordering trains to drive manually after the system locks itself down, is the proper procedure. Of course you are still supposed to only send trains to free sections, but the error is in that step, not that they ordered a train to drive on it's own.

Also the fallback procedure is also aided by automatic systems and a sizable number of accidents in the past were caused by that information being faulty.

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Yes, but just with max. 40km/h
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This really reminds you of the Chernobyl station computer printing all the warnings and recommendations to shut the reactor down when they started playing around with it ... and Comrade Dyatlov overriding it.

Dyatlovs seem to be born everywhere.

It should not be possible for one person to make a mistake of this magnitude. In case of a disconnected/off main safety system, the train should be limited on a hardware level to not be able to go over 40km/h.
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Reading the text it seems to me this is due to a very widespread issue in Spain and other southern European countries: people don’t care about the warnings because there are too many false positives.

That’s why people here, when they hear the fire alarm they just wait for it to go off: the probability that it is actually a fire is minuscule… but the alarm triggers a lot.

Not sure how to actually solve this… but I’m also not making excuses for what happened. High speed trains is not the same as a fire alarm in some office building, the people in charge should be held responsible somehow.

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I think aircraft are so safe in this regard because, essentially, they are required to use a single international collision avoidance system that is well defined. And modern cars have AEB systems built by vendors aiming for commonality to meet worldwide rules.

But train traffic systems seem to be a hodgepodge of different systems, perhaps locally grown and driven by the local vagaries of politics and rulemaking.

What a surprising inversion of expectations regarding safety.

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I'm totally not on the spectrum so I've only watched about 80% of the Plainly Difficult channel on YouTube, but if you want a painless and entertaining, if you're into that kind of thing, way of learning about train signaling and safety, and how safety systems have evolved, I highly recommend it.
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This accident seems to have been caused by human error. Moreover, (from the news) the working arrangements and procedures seem to be such that in the event of a controller (or driver) making a mistake there was no automatic failsafe protection in place to stop the Renfe train.

An automatic failsafe mechanism should be installed to stop/cut the power to the moving train in situations like this, it should work irrespective of any instructions or actions by the controller or the driver.

When safety parameters deemed the Renefe train to be travelling too fast and too close to the Iryo one it should have stopped automatically. Such safety measures aren't rocket science but straightforward engineering, (interlocks, etc.). Over the years there have been too many accidents in situations such as this for such equipment not to be installed.

For a moment I visualized myself in that busy control room and easily making that mistake even though I'd made the correct decision hundreds of times previously. Not only are 69 lost lives a terrible tragedy but the life of the person who made this momentary slip has been ruined forever.

It should not have been allowed to happen. It's worth remembering that Westinghouse brake systems (which are well over a century old) automatically default to on (stop) when there's a fault, and the high speed (now decades old) Shinkansen has very sophisticated stopping mechanisms and has never had a major crash. The question is why such safety measures weren't installed here.

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Earlier thread:

What we know so far about Spain train crash - https://news.ycombinator.com/item?id=50286197 - Oct 2026 (84 comments)

I still don't know why the train drivers don't have a simple data: The distance to the train that is next in in that railway in its direction. With this information, that accident will have never happened.
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There's like 100s location data on each train, do they not just have a map of where all nearby trains are.
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Human override could have 2 keys that get turned concurrently at two locations by people who never meet each other, never talk, each has different job incentives.
The main problem comes from under maintenance. I am spanish, we have known this for years.

15 or 20 years ago when I took the train it worked well.

Now there are more trains and they increased the traffic like by 70% if I am not wrong and the budget for railway infrastructure by only 17% and it seems to not scale well enough, for whatever reason I do not know all the details.

There are a lot of railway tracks that are not in good state so speed must be lowered. There are incideents and delays routinely, all the time.

This did not happen until like 10 years ago and it has gotten worse and worse since then, not only in high speed trains.

The roads is a mess also: 52% of infrastructure for roads has bad or very bad defects in it.

The thing is that we have a record in government incomings and the services, ALL of them (healthcare, roads, infrastructure...) slowly collapsing.Part of the money is not going to the right places. I think that nearly 40% of the budget goes for retired people. We have 9.5 million pensionists in Spain.

We have to change that system and rationalize government spending and welfare or eventually everything will collapse.

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This was a terrifying read because I initially read about this at the air port in Madrid after taking a Renfe train from Alicante; literally at the same time...just a different line
Off topic I know but, the BBC has adopted this clickbaity title pattern of “what we know so far about x” for the last year or so and it really jars me. Especially when x is very serious and involves people dying. It’s like an amateur tictoc’er is in charge of headlines at the moment.
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>In one recording, the controller tells the driver of the Renfe train to disconnect and reconnect the LZB mechanism that monitors train speeds, and then resume the journey at normal speed.

Wait, I thought Spain's high-speed rail network was all ETCS L1 or even L2?

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This event was pretty chilling for me because I just took the Renfe line from Seville to Madrid a couple of weeks ago while visiting Spain. I generally like to think that I have a pretty good instinct on relative risks and make reasonable decisions based on that. This time around, between the incident earlier this year and this most recent incident, depending on how you interpret and apply the statistics (of course that's always up for healthy debate), it looks like it would have actually been safer driving between Seville and Madrid. That's a pretty low bar in terms of safety!

I set my favorite agent on the task (Opus 5.5 in the Kagi Assistant), and given the two rail crashes in Spain this year, these are the stats it came up with for "chances of dying" via various modes of transportation between Seville and Madrid:

* EU high-speed rail, long-run average: ~1 in 36 million

* This rail line, counting both 2026 crashes: ~1 in 400,000 to 1.2 million (prior to the most recent crash it was 1–3 million; now ~2.5× higher)

* Flying with a European airline: ~1 in 80 million

* Driving: ~1 in 1 million or worse

Of course this is hindsight. Heightened awareness of risks, higher propensity to overreact to anomalies or alarms, procedural changes, and so forth in the wake of this second crash might push high-speed rail in Spain to be higher than the European average in the future.

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Is there an international consortium for best practices in high-speed train control? Surely there are countries that have good systems in place, or have benefited from knowledge-sharing. I have to believe these train systems were built with outside help and then organic improvement or the opposite. Spain, talk to them.
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At least California's high-speed rail will never kill anyone.
it's a matter of budget and political will. Spain simply cannot afford all these train lines, and the system fails. But hey, we have high speed train between Villacojón del Caudillo and Cagalera de la Reina, because they happen to be aligned to the center of the country (Madrit). These railways make no economical sense, they were built for political reasons, to support a "radial" concept of the country that does not really exist yet.

Meanwhile no high speed rail between València and Barcelona, because that would somehow erode the power of the central elites.

I can't imagine what every passenger who survived and the families of those who passed are going through. Such a catastrophic incident with multiple human failures is so tragic and so needless. From the controller to the driver, every single one of them should have said hey we shouldn't just ignore a signal and should investigate why it's on first. For this to be such a quick decision suggests it's not a one off. I would be extremely interested to see how many near misses or ignored signals there has been across Spain. The crash earlier this year was due to inexperienced workers and it seems as if significant training improvements and protocols are needed.
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The BBC keeps repeating this inaccuracy and at this stage I wonder if it's deliberate:

> The driver replies, "At normal speed?" To which the controller says: "Yes."

That is not how the conversation went. The driver reads back the order from the controller, saying "at normal speed? Hm okay agreed / understood" then the controller starts wrapping up the conversation

ie the driver did not really question the order and it was barely a questioning tone (I write without judgement)

You only need intermediate Spanish to understand that part of the clip. The BBC has no excuse to be honest as I'm sure they have plenty of native speakers on hand

Whether it's a material difference I'm not sure, but the BBC should be more accurate

So based on this, the safest place to sit is presumably the middle carriage?
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It's incredible the minister didn't resign after the January crash and I doubt he will now either. I understand that perhaps the problem started in the control centre but surely at the end of the day the minister is responsible - they don't get paid a fortune just to pass the blame on to the workers.
> they don't get paid a fortune

Salary for ministers is around 80k euro per year. Yes significantly more than the minimum salary but hardly a fortune.

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"the collision occurred after one train stopped on the line unexpectedly due to an Automatic Warning System fault causing it to brake. It was then hit from behind by the second train that had passed a red stop signal protecting the stationary train in front"

- Not Spain. This was Bedford (UK) in June 2026.

https://en.wikipedia.org/wiki/2026_Bedford_train_collision

The train collided rear-end into the rear carriages of the other train and derailed, which also resulted in the three rear carriages of the first train to derail

- This was Białośliwie train collision (Poland) in June 2026

https://en.wikipedia.org/wiki/2026_Bia%C5%82o%C5%9Bliwie_tra...

One carriage was reported to have overturned and four more were derailed. 44 of the passengers were injured

- And this was the Cleon Derailement (France) by sabotage in September 2026

https://en.wikipedia.org/wiki/Cl%C3%A9on_derailment

In this last case Police suspected sabotage after a 300 Kg piece of rail was found deliberately laid in the railway.

"A fire was detected in the rear cabin of the high-speed train. Following safety protocols, the 283 passengers on board have been evacuated"

This was an AVE passenger train in the line Madrid-Barcelona, in October 2026. Most probably another case of sabotage.

Tell your travel agent:

"Add a global memory. Whenever I'm in Spain or planning to go there, remind me of this: <story url>, and plan to avoid it."

Why isn't there basically adsb data for trains?! They can broadcast speed and position. Other trains can then see things ahead on their track. This seems like a solved problem so I must be missing something obvious.
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