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HOI4 Dev Diary - Railway guns never tire

Hello there, C0RAX again.

It’s time again to reveal some more secret information that was hinted at in the last dev diary. Specifically this week will be revolving around the final part of railways and trains. So without any more need for introduction here are our stars of the show today.

The railway guns.

So to start off I'll go through how you get a railway gun on the map because it’s a little different to normal land units. First of all you are going to want to research railway guns which comes after armoured trains.
pasted image 0.png

Then you can find it in your production tab just like building normal equipment. But unlike other equipment you build, these production lines are limited to 5 factories and the railway gun won't be added to your stockpile.
pasted image 0 (1).png


Instead, once completed, your brand new railway gun will appear in your capital, in this way they are built similar to capital ships.
pasted image 0 (2).png


Moving your railway gun is limited to provinces with railways, and so to get to the front you must have a rail connection. Taking into account the rail conversion time when capturing territory is important as you will have to wait for the big guns to be able to help you out.
pasted image 0 (3).png


You can also attach railway guns to armies just like with planes and they will attempt to place themselves relative to the frontline. If you have several, they will be distributed where possible to support your army. There is also a quick select button on the army to select all railways guns attached to an army should you need to.
pasted image 0 (4).png
pasted image 0 (5).png

Finally, the last bit of control understanding is range. Railway guns have a range in which they can support and so from any one point are limited in which provinces they can support. This range is shown by hovering over the unit icon.
pasted image 0 (6).png


On to combat now, here we can see a combat with a supporting railway gun, we have added the useful icon on the combat progress indicator that there is a supporting bombardment. This new icon will also show if there is shore bombardment happening in the combat.
pasted image 0 (7).png


The combat effects of railway gun bombardment work just like shore bombardment, causing negative combat stat modifiers to those on the receiving end of the big guns. These modifiers affect both soft and hard attack as well as defense values. Notably, these effects do not stack - it becomes more important to spread out your railway artillery than to concentrate it.
pasted image 0 (8).png


Finally we need to talk about capture and damage, railway guns can be captured via encircling them and damaged by damaging the railway they are placed upon.

Now railway guns are the biggest guns by far used on land and so it's important that we have representations of those built by the major powers. So now we look at the unique guns for the major powers.

This is the German Schwerer Gustav model you will see when playing as the Germans. It's perhaps the most famous railway gun and definitely the biggest and so had to have a part in this feature.
pasted image 0 (10).png

This is the BL 9.2inch railway gun, a relic of the first world war but these big guns were kept in service until 1945.
pasted image 0 (11).png


Following that we have the French Canon de 305 another veteran of the first world war.
pasted image 0 (12).png


Next up is the USA’s 8-inch Mk. VI which remarkably first entered service as late as 1941!
pasted image 0 (13).png


Type 90 240 mm railway gun whose claim to fame is being destroyed by the retreating Japanese in the soviet invasion manchuria.
pasted image 0 (14).png


And finally the TM-3-12, three of these were made in 1938 and were used in the winter war against finland, unbelievably these where in service until 1999 (a whopping 61 years of service)
pasted image 0 (15).png


Finally here's a cool clip of the Schwerer Gustav firing in game.
Railway-1.gif
 
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some german railway guns were used as costal defense
most uk railway guns were also used as coastal defense

Strait of Dover

After the Fall of France Germany added 58 captured French guns to its inventory while Italy was given 19 French guns with many of these being captured by the Germans after the Italian capitulation.

To find out more it seems to be neccessary to buy a book: Railway guns of World War II. Dennis, Peter. Oxford: Osprey. ISBN 978-1472810687.

Does the dlc may contain a pdf of this book?

 
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but expect for Gustav and Dover Strait i cant find any good informations what happened to the 58 captured french guns. And what did italy with 19 captured french guns ?

maybe most of it were destroyed somewhere


very small and absolutely not much information

example: https://en.wikipedia.org/wiki/Krupp_K5 25 of these were built and the NATO later used it to construct the M-65 atomic cannon

Anzioanniegun.jpg


Krupp K5 "Leopold" in the United States Army Ordnance Museum
 
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Will trains be used to move resources across provinces too? It'd be super cool if when you put a new factory to construct or try to produce new equipment trains would be sent to the ports to move the imported resources to your factories and build the tanks and small arms.
Also, will we be able to bomb the railways? Thus maybe affecting supplies in the region similar to how strat bombing infrastructure works?
 
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but expect for Gustav and Dover Strait i cant find any good informations what happened to the 58 captured french guns. And what did italy with 19 captured french guns ?

The Italians turned most of them into scrap IIRC and used the iron and shit to make tanks and small arms. Similar to what the allies did with Italy's Regia Marina ships in the post war.
 
I actually made this suggestion a while ago (well, not railway guns specifically) : could the guns be produced at a shipyard ?

After all, a railway gun is a heavy railway carriage with a naval gun....

Oh, and about a key problem of those guns-accuracy at maximum range) an obscure comic actor once made a movie that was somewhat disparaging toward a German politician, that movie lncluding a demonstration of the tactical problems of such guns....


That is, at a range where you cannot be subjected to counterbattery from campaign guns, let alone other heavy guns, the imprecision is such that any tactical objective will be missed (even hitting a metropolis is not given). The ''Big Berthas'' of 1914 for instance were quite effective, but firing a 9000 metres (well into the range of campaign guns). While a large percentage of the shells of the Paris Gun managed to miss Paris.
 
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The Italians turned most of them into scrap IIRC and used the iron and shit to make tanks and small arms. Similar to what the allies did with Italy's Regia Marina ships in the post war.

A very minor point, but a number of RM ships lived on in non-Italian navies post-war, the biggest was the Soviets taking one of their battleships, but the French also used one of the destroyers and/or light cruisers (I can look up details later if interested, but it's early and I've got to keep moving). The Allies also gave back some of the ships to Italy so they could be scrapped there (Italia and Vittorio Veneto being the biggest, by some margin).

I don't know what happened to those ex-French railway guns though, and given resource shortages in Italy scrapping them for material is a very plausible outcome.
 
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but expect for Gustav and Dover Strait i cant find any good informations what happened to the 58 captured french guns. And what did italy with 19 captured french guns ?

maybe most of it were destroyed somewhere


very small and absolutely not much information

example: https://en.wikipedia.org/wiki/Krupp_K5 25 of these were built and the NATO later used it to construct the M-65 atomic cannon

View attachment 755600

Krupp K5 "Leopold" in the United States Army Ordnance Museum
I know the Obusier de 520 was deployed in the siege of Leningrad and was lost to a premature ammunition detonation (in French use it had been planned to be used to bombard the Westwall, but the ammunition wasn't delivered prior to the fall of France). At least some 274mm guns were used by Germany for coastal defense similar to the K5 (and were additionally also similarly pressed into the occasional in-land role, including one particularly well-known gun that had been named Bruno by its new owners (the Germans seemed to name a lot of guns Bruno)). I believe the French 320mm GI gun (not to be confused with the 320 mm bercaeu guns) was primarily used by both the French and Germans for counter-battery fire. The 194mm TAZ modele 1870/93 was used exclusively for coastal defense by the Germans. The 240mm TAZ modele 1893/96 was also used for coastal defense, including in Narvik. The Italian Liberation Corps took at least two 194mm TAZ modele 1870/93 guns and used them in the Monte Cassino front. Like other Italian war-booty 194mm TAZ guns, these had their armored roofs removed.

Source on all this: Railway Guns of World War II by Steven Zaloga

Also I don't believe any actual material from any K5 gun was used in the construction of Atomic Annie, it just took some design inspiration for the actual carriage.
 
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The Italians turned most of them into scrap IIRC and used the iron and shit to make tanks and small arms. Similar to what the allies did with Italy's Regia Marina ships in the post war.
Italy definitely used and modified at least some of the 12 194mm TAZ modele 1870/93 guns they claimed, cutting off their roofs to make them more usable in the warmer climates they were using the guns in. At least two of these guns were then claimed by Italian rebels and used against the Italian state in 1944.

Edit: I believe at least another three had to be preserved because Germany took possession of them after Italy fell to the Allies.
 
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By the way, to explain some of terms in those guns' names, TAZ is short for Tous Azimuts or All-Azimuth. Basically it's a turreted gun. GI is short for Glissement or Sliding. This means the recoil of the gun is absorbed by simply allowing the carriage to roll backwards on its tracks. Berceau or Cradle means that the carriage remains more or less in place and the recoil is absorbed by hydraulic or hydro-pneumatic recoil cylinders, much like modern non-railway artillery.
 
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Well, I wish this mechanic was applied to usual artillery (with more severe modifiers and actual damage) cause it's somewhat confusing and unrepresentative when these have to fight on the frontline. Nice diary though!
 
Will the Railway Guns be modifiable like planes or tanks? Mainly concerning the range and maybe the caliber of the gun?
Cause let alone Germany had different approaches to them, Schwerer Gustav was a real exception, with only two guns being built. They also planned the "Langer Gustav" (Long Gustav) with less caliber (60cm I think) but longer gun, designed to shoot over the Channel to England. The majority of the Railway Guns were though of smaller calibers.

So I don't know, maybe two modification-options, one range, one caliber, and upgrading them increases the production cost and reduces the speed, of course.

I think would be quite a nice idea :)
 
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Hello there, C0RAX again.

It’s time again to reveal some more secret information that was hinted at in the last dev diary. Specifically this week will be revolving around the final part of railways and trains. So without any more need for introduction here are our stars of the show today.

The railway guns.

So to start off I'll go through how you get a railway gun on the map because it’s a little different to normal land units. First of all you are going to want to research railway guns which comes after armoured trains.
View attachment 754461
Then you can find it in your production tab just like building normal equipment. But unlike other equipment you build, these production lines are limited to 5 factories and the railway gun won't be added to your stockpile.
View attachment 754462

Instead, once completed, your brand new railway gun will appear in your capital, in this way they are built similar to capital ships.
View attachment 754463

Moving your railway gun is limited to provinces with railways, and so to get to the front you must have a rail connection. Taking into account the rail conversion time when capturing territory is important as you will have to wait for the big guns to be able to help you out.
View attachment 754464

You can also attach railway guns to armies just like with planes and they will attempt to place themselves relative to the frontline. If you have several, they will be distributed where possible to support your army. There is also a quick select button on the army to select all railways guns attached to an army should you need to.
View attachment 754465View attachment 754466
Finally, the last bit of control understanding is range. Railway guns have a range in which they can support and so from any one point are limited in which provinces they can support. This range is shown by hovering over the unit icon.
View attachment 754467

On to combat now, here we can see a combat with a supporting railway gun, we have added the useful icon on the combat progress indicator that there is a supporting bombardment. This new icon will also show if there is shore bombardment happening in the combat.
View attachment 754468

The combat effects of railway gun bombardment work just like shore bombardment, causing negative combat stat modifiers to those on the receiving end of the big guns. These modifiers affect both soft and hard attack as well as defense values. Notably, these effects do not stack - it becomes more important to spread out your railway artillery than to concentrate it.
View attachment 754469

Finally we need to talk about capture and damage, railway guns can be captured via encircling them and damaged by damaging the railway they are placed upon.

Now railway guns are the biggest guns by far used on land and so it's important that we have representations of those built by the major powers. So now we look at the unique guns for the major powers.

This is the German Schwerer Gustav model you will see when playing as the Germans. It's perhaps the most famous railway gun and definitely the biggest and so had to have a part in this feature.
View attachment 754470
This is the BL 9.2inch railway gun, a relic of the first world war but these big guns were kept in service until 1945.
View attachment 754471

Following that we have the French Canon de 305 another veteran of the first world war.
View attachment 754472

Next up is the USA’s 8-inch Mk. VI which remarkably first entered service as late as 1941!
View attachment 754473

Type 90 240 mm railway gun whose claim to fame is being destroyed by the retreating Japanese in the soviet invasion manchuria.
View attachment 754474

And finally the TM-3-12, three of these were made in 1938 and were used in the winter war against finland, unbelievably these where in service until 1999 (a whopping 61 years of service)
View attachment 754475

Finally here's a cool clip of the Schwerer Gustav firing in game.
View attachment 754497

at the most and best capacity will be able to fire a projectile more than 200 nautical miles at a muzzle velocity of Mach seven also impacting its target at Mach five. Projectiles are guided to the target after leaving the launcher, and reach a target faster.
 
You should inform ww2 generals about this revelation. Massive artillery like railway guns were constructed and used specifically to defeat fortified positions. And they were used in this role.
Steven Zaloga, one of the foremost experts in WW2 historiography history, wrote Railway Guns of World War II wherein he enumerates the advantages, flaws and also the shortcomings of railway guns and the battles where they were used during WW2. You can check that out since it's free at Library Genesis.
 
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is this a pre cursor for all Artillery? Adding range and a debuff to combat as opposed to adding to Soft attack and width?

Note the 8 inch-203 howitzer the US Army used in WWII, it was on a wheeled chassis, two of them to be exact and used modified M-10 Wolverines and M-3 Lee medium tanks as tractors. https://en.wikipedia.org/wiki/8-inch_gun_M1. 139 built and used between 1944 and the end of WWII
 
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