Thread by @Danny_elMayor

THREAD.

Civil protection and shelters of Czech capital. Prague final line of defence in case of nuclear or conventional war and natural or industrial disasters.

Prague underground.

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Lets get right into it. When talking about civil protection system of Prague. The most important and most capable is its metro. How? Well. Because Prague metro system isnt your usual metro. Apart from the basic transportation and the "standard" that passengers see everyday

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Metro of Prague has its hidden side.

Most of Prague metro was build during Cold War (1st line opened in 1974) so there was a project that was build alongside the metro itself, using it as a camouflage for the real extent of work. It is expected that this project cost

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About 50% of the whole metro buildup.

We are talking about OSM. Ochranný Systém Metra (metro protection system).

It means that most of metro system itself is a one gigantic shelter, that in current state can provide protection for about 330 000 people.

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OSM is being classified as STOU (stálý tlakově odolný úkryt - permanent pressure resistent shelter) and protects from shock/pressure wave, penetrating radiation, radiation contamination,light and heat impuls and chemical and biological weapons.

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It is made possible not only because of depth itself (deepest station is 55m underground), but thanks to series of solutions utilized. In case of danger. Most of the metro system will be hermetically sealed thanks to blast doors in the lowest part of the stations.

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STOU-classified stations have blast doors to close the tunnels between them. Plus, there are more blast doors in the tunnel system itself.

This means that even if one part is compromised, the rest is safe.

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STOU classified stations offering high protection are:

A-line from Dejvická to Skalka station (12 stations - 116 000 people)
B-line from Nové Butovice to Českomoravská (14s. - 130 000)
C-line from Roztyly to Háje plus Vltavská and Nádraží Holešovice stations (6s. - 85 500)

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So from the 65km long Metro, the decent portion is a bunker if needed.

Of couse. The tunnels and stations alone are not enough. Thats why stations and tunnels have their "secret" parts, that are not accessible to public. And contain technical hardware, storages,

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smaller tunnels, extra rooms, some have decontamination rooms and control rooms. Also OSM is connected to other places via tunnels, for example to some underground garages in centre of Prague that are also equipped with blast doors.

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Prague magistrate states that apart from central OSM system, there are 38 more STOU-classified larger shelters in Prague. Some of them connected to OSM. Some not.

One of the most interesting of such objects in my opinion is Strahov tunnel.

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On first sight. Nothing interesting. Normal tunnel for cars, part of tunnel system that goes from north to south of Prague.

Yet. In case of danger, it will be hermetically sealed from both entry points thanks to 40-ton blast doors on each side and more blast doors inside

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Inside the tunnel, there is more rooms, storages and technical rooms. Strahov tunnel can provide protection for 15 000 people.

What is interesting. From the tunnel leads underground way that connects it to B-line of the metro and its OSM.

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Now about connection. Prague underground, especially in the city centre is vast and complex, from different time periods. So appart from metro and OSM tunnels, or some possible secret tunnels between government buildings. There are two more main types of connections.

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First being Prague collector system. It currently has over 90 km in length, width and height differs a lot. While it isnt STOU-classified, it is buried 35m below ground in some places, about 20-25m in general, so still offers some decent protection for underground movement

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And second one being old Prague underground and sewage system. Not as a great shelter per say, more like possible transit route or emergency case shelter (from penetrating radiation for example). Once again. Prague below ground is vast, deep and often connected.

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Now lets go from OSM and connections to some larger separate bunkers that still could offer decent protection. One of them is bunker under Vítkov national memorial. Capacity: 1 200 people. Own power (generators) and water source (5 deep wells). Air filters and circulation.

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Vítkov bunker is being kept in good condition by Prague city services. Second for example is Bezovka bunker complex. Capacity: 2 500 people.

They should also be STOU-classified. Around 30 more larger objects should exist. Types varies (like said garages).

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On top of that, there is 650 smaller shelters in Prague. About 200 owned by state, rest in private hands (companies, owners of houses etc.).

In total. All objects of OSM and other shelters should provide protection for up to 450 000 people for 72 hours.

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After finishing of D-line (currently being build), and inner circle (E-line). The number should rise to 600 000

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Deepest metro stations were designed to withstand direct nuclear strike. But please. keep in mind, that this protection system isnt only for this "endgame" scenario, but also natural and industrial disasters, and in large scale war,

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it offers great protection against offensive conventional munitions like cruise missiles. Looking at what is happening in Ukraine, how cities are being shelled again and again. This seems like a good thing to have.

Now lets go to some interesting shelters.

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First is object K-111 Klárov. Secret until recently, its actually the first metro station in Prague, that never came to be a metro, but a government bunker. It is ready to use now as well. We can only speculate if its connected to shelter under Prague Castle, or to MoD

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Another is object KO-17. Sheltered underground hospital under Thomayers Hospital. It is ready to use in one hour after alarm. Some say its somehow connected to OSM.

Protected underground hospital can be also found under Bulovka hospital.

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There is more, like object K-116, or some object, where was supposed to be a reserve high performance radio tower, hidden under ground, and extended after bombs stopped falling, to be able of transmission all over Europe. If it exists/is operable. Who knows...

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About warning system. There is a large amount of sirens all around Prague. And they are being checked every single month.

Every first wednesday of new month, sirens are turn on for several minutes, to check if they are working.

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Now before we end. One thing has to be said. The OSM and all other shelters, dont currently have material reserves like food, medical supplies, beds, water. So they are not good to go right now. The thing is, that the hard part, all the rooms, and infrastructure is there.

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Its easier to send in all the supplies, do all the checks and preparations. Because thats the matter of weeks/months for full preparation. To then be ready to work on short notice. But to build all of that from ground up (or down in this case). That would be years/decades

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For example. Medical equipment can be provided by Czech Armed Forces medical service, that have build recently field hospital during covid.

Of course. Hopefully this wont be ever needed. But better be safe than sorry.

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And once again. Dont think neccessarily about nuclear strike, and all that end time scenarios and "real life Metro".

There are other ways to do harm. For example. Vltava cascade. This huge waterwork which consists of series of 9 dams on Vltava river, is over Prague.

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During Cold War. There were plans to actually strike the dams, to cause massive flood way that would damage lower parts of Prague severely.

In todays age of "little green man", drones, unconventional warfare etc. This can be bigger more real danger than nuclear strike.

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So its good that Czech Armed Forces are boosting protection of such critical infrastructure, with buildup of 14 territorial defense battalions, that are tasked with ODOS (critical infrastructure for defense of the state) protection.

About the "water threat"

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In 2002. During the largest floods in 100 years. The OSM partly failed, because it was decided to close it too late, plus there were some issues with isolations of some components. So some stations ended under water...

While costly, system was improved and reworked

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So the "lessons learned" were applied. Still. Massive flood wave gives little reaction time, yet, we can expect that in case of immediate reaction. OSM can be sealed in time to hold off the water (not only bombs and radiation).

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Prague civil protection system, offers a decent protection, while utilizing other infrastructure and I dare to say its something unseen in western Europe.

It isnt perfect. But it certainly increases the overall safety and survivability of people in times of crisis

END

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