I recently took the first direct train from Prague to Copenhagen which was expected to take 13 hours from PRG to CPH (normally it should be 11 but there is a construction on the high speed line between Berlin and Hamburg so we had to take a detour through Uelzen).

The train left the Czech Republic with 0 minutes delay. Long story short, we crossed the German-Danish border more than FIVE hours later than the original plan. And it wasn't even in the same physical train, the original one got cancelled from Hamburg because of the huge delay we already had.

As for the reason of the delay, at first it was just German "normal" state of things, we left Bad Schandau (the first German station) on time, got to Dresden with 5 minutes (still "on time" according to DB), then without any visible reason got 20 minutes on approach to Berlin where there were so many people on the platform that it took some other twenty minutes for the passengers to get on and off.

When we arrived to Luneburg, the train stopped and after an hour or so the crew said that there is a problem on the line to Hamburg so we'd have to take another detour (from a detour!) and go through Hannover which added several hours to our delay. On approach to Hamburg we already knew that we'd have to transfer to a Danish train there, which thankfully went pretty fast and we left for Schleswig, where our train stopped again, this time because of a "fire in the vicinity of the tracks". After another two or three hours that it took the firefighters to realize that nothing was actually burning, we finally left Germany and the rest of the trip went just fine and we did not gather any additional delay in Denmark, arriving to Copenhagen in the middle of the night (instead of the original 7:30pm).

TL;DR: Sänk ju for trävelin wiß Deutsche Bahn!

Czech media even wrote[1] about how the train failed to get to its destination.

[1]: https://zdopravy.cz/prvni-primy-vlak-z-prahy-do-kodane-skonc...

There's even a website gambling on how late DB trains will be.

https://bahn.bet/

The Rostock bridge was proposed and this tunnel selected instead.

My understanding is that the water farther east is shallower which makes bridge cheaper. But not enough to be chosen.

Yes, and it would have required much more investment in rail upgrades in eastern Germany. I can understand why they didn't go for it.

It's not in an earthquake zone, but isn't the Scandinavian continent still rising at a surprisingly fast rate? I wonder if that could affect the engineering of the Fehmarnbelt tunnel, in an "in x years one end of the tunnel will have risen n centimeters compared to the other end" way. It's probably such a small amount it's well within levels where regular maintance will cover it anyway, but I'm still curious.

See how dangerous road conditions out in the open can be? This won't happen to you in a tunnel! Consider commissioning one with us today :)

When the iron curtain fell, there were big plans and a formal contract about modernizing the rail link between Prague and Nuremberg (a hugely important connection on the days of Charles IV). The Czech side eventually stopped electrifying their parts when they realized nothing happened on the other side of the border. These days, Deutsche Bahn is operating a _bus connection_ between the cities. It seems like they are solely focused on beating imaginary Autobahn times between a selected set of major German cities, and consider everything else a nuisance...

The exact same thing is happening with the Gotthard Base Tunnel. Switzerland has completed it almost 10 years ago, Germany still hasn't finished the links.

It is combination of the German planning system, which allows the processes to be stretched out due to objections, and spineless politicians who don't really want to commit to a route and kick the can down the road (because whatever they do, someone will be angry; but voter's don't really make you responsible if the link isn't built or is delayed).

Very much depends on the site - certainly there's plenty that are annoying in the way you describe, but there's also plenty (I wouldn't be surprised if either side were the majority) that will take you to the exact same content on the more local version of the site.

A video posted in another thread says the segments are sealed with bulkheads, floated into position, submerged by allowing water into a ballast section, dropped into place , aligned with pins, drawn to the next segment with hydraulic jacks, and sealed to it with rubber gaskets. Then the bulkheads can be removed. The gaskets also allow for some thermal expansion.

I'm curious what the lifetime of those gaskets might be and how you might maintain them.

Here’s a fun video about how one sunken tunnel was built in Vancouver back in the 50s. https://youtu.be/A1igKk8eK0M

That’d be awesome. What is the current tallest ship that could damage a bridge? You can count on someone eventually doing that.

I think it isn’t that deep - last time I checked it was reasonable, but you make a good point about unexploded ordnance. Building it would be a thrill.

Getting to 200 was mostly a matter of upgrading tracks that needed maintenance anyhow in the 90s, in the 90s however cargo traffic wasn't causing as many disruptions and congestion as today and the talks about "new exclusive" lines is mainly meant to shift air-traffic to faster AND non-congested lines, but new lines are far more expensive/prohibitive both due to new land requirements and making it a "big-bang" build.

Agreed, I got carried away

Of course they are comparable. They are both mechanisms to get people from point A to point B

I really hate how German environmental activists resort to hyperbole and alarmist language by default when voicing concerns. This only makes it harder for me to take them seriously.

And then there is this tried and true tradition of commissioning studies with the sole intent to support a predefined viewpoint rather than taking an unbiased approach. This makes it so hard to trust any information when political arguments become heated.

To make the connection back to the tunnel: it consumes a huge amount of concrete and that releases the associated amount of CO2. Thisnpart is fairly easy to estimate. But estimating the impact on traffic emissions is fraught with issues. There are so many assumptions about lifetime, amount of traffic, types of vehicles that I can easily imagine the error bars to stack up to the point where a little tuning of model parameters gives just about any desired result.

From a Danish perspective I don't really see any positive long, or short, term gains from the Fehmarn tunnel, but I also live in the wrong part of the country.

This is a tunnel for Sweden, Norway and Copenhagen, it's moving the center of everything in Denmark closer and closer to the center of Copenhagen, completely disconnecting the rest of the country. A few days ago a new train start running Copenhagen to Oslo, a seven hour trip. That's the same time it takes me to get to Copenhagen by train within Denmark. Everyone is happy that you can "Get on the train and just pop to Hamburg, Berlin or Prag", but you can't, only if you happen to live in a few select spots does that work. It's a multi-day journey with a layover within the country if I want to leave by rail.

Internationally this is a great project, internally in Denmark, it's going to make international train travel worse for the majority of the country.

> Do you have a source for how little maintenance this will need?

In Germany, twice a year inspection is mandatory for infrastructure [1] but this is only a visual inspection. Once every 6 years you got a large inspection [2] that includes a full go over everything including functionality checks plus a review of documentation (if it is still up to code) and of accident documentation, as well as a "knock test" on every m² of surface [3]. Fire safety systems are checked every quarter [4].

And out of these reports then you get action items. Depending on the severity of findings, it can be anything from "someone needs to do this until the next major inspection" to "holy cow stop ALL traffic NOW".

[1] https://www.stbapa.bayern.de/service/medien/meldungen/2023/2...

[2] https://www.fba.bund.de/DE/Meldungen/20230201_Tunneluntersuc...

[3] https://www.merkur.de/lokales/muenchen/baustellen-besuch-sta...

[4] https://www.autobahn.de/aktuelles/aktuell/tunnelwartung-im-b...

Definitely I am making a broad assumption with many specifies where one can say "but what about X,Y,Z". Certainly, there are buildings that fall down and bridges collapse but what is the trend? Is software engineering getting better or worse?

From the linked article:

> And I would say that the success of AI coding agents has proved once and for all that we had successfully built an engineering discipline so strong that we are also the first discipline that has been able to successfully run AI at large scale within our discipline.

Yet we have no real clue how AI works or how to debug it, it's a brute force solution to everyday problems. Daily there are new examples of AI "escaping" its enforced cage. Why? Why doesn't AI "just work"? Because we don't truly understand AI.

I think AI is exactly the opposite to "true" engineering where one understands the system and can reproduce it. After all, retraining the AI will probably give you a completely different AI even if the training data was the same.

When you say Engineering is not that complex, have you taken into account corrosive sea water, pressure, currents, what it means to make repairs and maintainance down there etc? It is difficult, because it deals with a very complex world full of physics, chemistry and even biology in a way that does not allow errors.

Software isn't inherently complex, it becomes complex. Because it is iterative. Because we keep making demands of it that weren't planned.

Imagining building a bridge and then in the middle someone comes along and says it should also be a tunnel. I think therein lies a main difference to engineering and software engineering: planning and sticking to a plan.

Another thing are incentives: real engineering has real incentives to do it right, else you will get sued - by the families of those that died. Software engineering does not have this incentive to get it right.