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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.
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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.
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Instead, once completed, your brand new railway gun will appear in your capital, in this way they are built similar to capital ships.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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Following that we have the French Canon de 305 another veteran of the first world war.
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Next up is the USA’s 8-inch Mk. VI which remarkably first entered service as late as 1941!
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Type 90 240 mm railway gun whose claim to fame is being destroyed by the retreating Japanese in the soviet invasion manchuria.
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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)
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Finally here's a cool clip of the Schwerer Gustav firing in game.
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So let me get this straight:

You have to spend research time, 5 factories at a cost of 20 steel, 10 tungsten and 10 chromium to build 1 of those 800 IC behemoths, that can only support 1 combat at a time so long as it is close enough to a railroad to be in range, and that railroad has the right gauge, to get a maximum effect of -15% on enemy stats? Which is the same bonus a lvl1 fort would provide? And after doing all of that, if the enemy pockets it, can capture it and use it against you for free?

In what scenario will this be a sensible investment instead of assigning those 5 factories and resources to tanks, fighters or CAS?

Wouldn't it make more sense if they provided bombardment bonuses similar to CAS?

Not being sarcastic, just trying to understand the purpose of these.
800 Ic a medium tank brigade. Or ~30 CASII.

Considering the "meta" of spamming 15+k cost heavy tank divisions, getting -15% bonus on enemy armor counter-attacking yours seems like the best investment you can make. As for CAS, good luck with that, considering air attack of 2-4 heavy SP-AA.
 
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Ooooh, hello Stanier 8F, looking very snazzy in LMS red there. I imagine that the upgrade from that will be the Austerity 2-8-0, which the additional option of getting some S-160s from the States. Me likey.

Good thing that the Brits have the BL 9.2 inch, if they'd have been given the BL 18 inch you'd have to model infrastructure damage to the surrounding province every time it fired. :D
 
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By the way, it is interesting that the Soviet TM-3-12 was produced at a shipyard. It would be interesting that it would be possible to attract shipyards for the production of non-ships: railway guns, tanks, etc.
 
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I am intrigued by the mechanics behind this, and the possibility of modding or expanding the mechanisms, to allow for corps level assets that can be assigned to groups of divisions, rather than directly to divisions.
Stuff like... field hospitals, forward repair depots, corps level artillery, and so on. Maybe even those "independent heavy tank battalions" that people occasionally mention that the Germans use.
 
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Thought experiment:
  1. Build a single tile of rail in Honolulu.
  2. Ship in a railway gun.
  3. Enjoy additional defense in most* of the Hawaiian Islands.
Does this sound right?

Other fun things to try:
  • Park a railway gun in Saipan to blast defending forces out of Guam, or vice versa.
  • Railway gun in Egypt to defend Alexandria and El Alamein at the same time.
  • Railway guns in northern France to blanket defense across every potential D-Day port.
  • Railway guns in southern England to provide invasion support across same.
*Based on the range depicted on the Romanian gun, which can apparently fire from Ploesti to across the Danube.
 
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Thought experiment:
  1. Build a single tile of rail in Honolulu.
  2. Ship in a railway gun.
  3. Enjoy additional defense in most* of the Hawaiian Islands.
Does this sound right?

Other fun things to try:
  • Park a railway gun in Saipan to blast defending forces out of Guam, or vice versa.
  • Railway gun in Egypt to defend Alexandria and El Alamein at the same time.
  • Railway guns in northern France to blanket defense across every potential D-Day port.
  • Railway guns in southern England to provide invasion support across same.
*Based on the range depicted on the Romanian gun, which can apparently fire from Ploesti to across the Danube.
well that is kind of how the Germans used them in Italy at least. Their range is pretty impressive. The question is how much fights can it support at the same time? If I attack at several states at the same time, it should only support one. Still making it strong (which it should be) but not impossible to beat.
 
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is it possible to use railway guns to make life more difficult against ships that are bombarding the shores? if you look at it during ww1, italians used railway guns as a way to harras the austro-hungarian navy on the adriatic coast.
 
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Could the railway guns be repurposed for coastal defence?

This type of artillery are essentially a battleship's main guns...

Maybe stick them in a division template and assign it 'Coastal Defence' mission for garrisons, not unlike Naval Bombers.
 
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Very interesting, id like it.

I really hope that the production time of railway guns and its price will be included correctly . I really hope so.

Example:

https://en.wikipedia.org/wiki/Schwerer_Gustav

Weight: 1350 tonnes

please compare to a Tiger tank weight 55 tonnes. So 1350 / 55 = 24,5 . That would mean to building 1 schwerer Gustav railway gun you could build 24 tiger tanks. Or need 24,5 times more time to produce just 1 Gustav than to produce 1 Tiger tank. 250 + 2500 manpower needed,too(maybe 4000 manpower or more were needed for the real gun usage). Same with price 250k for a Tiger , 7mill for 1 Gustav.

Loosing some of these railway guns could cause stability loss

In order to produce and build these cannons quite a bit(or huge number) political power must be spend

Theyre so expensive

DoraVSScarab.svg.png


also important please dont forget the italy railway gun https://en.wikipedia.org/wiki/Cannone_da_381/40_AVS (in real war it was NOt mobilized, but it could be? couldnt it?)
 
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I hope railway guns are fairly vulnerable to bombing if you don't have good air-superiority. I imagine a gigantic gun like the Gustav would be a massive target for a large number of CAS/TACs
 
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Very interesting, id like it.

I really hope that the production time of railway guns and its price will be included correctly . I really hope so.

Example:

https://en.wikipedia.org/wiki/Schwerer_Gustav

Weight: 1350 tonnes

please compare to a Tiger tank weight 55 tonnes. So 1350 / 55 = 24,5 . That would mean to building 1 schwerer Gustav railway gun you could build 24 tiger tanks. Or need 24,5 times more time to produce just 1 Gustav than to produce 1 Tiger tank. 250 + 2500 manpower needed,too(maybe 4000 manpower or more were needed for the real gun usage). Same with price 250k for a Tiger , 7mill for 1 Gustav.

Loosing some of these railway guns could cause stability loss

In order to produce and build these cannons quite a bit(or huge number) political power must be spend

Theyre so expensive

View attachment 754549

also important please dont forget the italy railway gun https://en.wikipedia.org/wiki/Cannone_da_381/40_AVS (in real war it was NOt mobilized, but it could be? couldnt it?)
i mean it was used during ww1 so why the hell not?
 
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i dont know, maybe to mobilize an old gun for italy could need a decision, iam not sure

Of course italy could produce new ones, too. But i dont know wich type. Maybe the italy gun will arrive as planned (they could be more punctual if there would be another decision for italy would be active)
 
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Regarding Army attachments, what are those 2 on the left?

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i dont know, maybe to mobilize an old gun for italy could need a decision, iam not sure

Of course italy could produce new ones, too. But i dont know wich type. Maybe the italy gun will arrive as planned (they could be more punctual if there would be another decision for italy would be active)
is not that much of a problem since the old ww1 guns where stored in Rome it was simply a matter of taking them out of storage to use them, and potentially that was the idea at first from what i understood.
 
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Railway guns were also used as a strategic weapon with various other uses outside battle mainly as a tool for destroying enemy fortifications. Do railway guns have the ability to passively damage some buildings or to do so while supporting a battle? Would be nice if it had a bit of strength/organisation damage and building damage similar to say air missions that support a battle, this effect should also probably be extended to shore bombardment too.

Secondly is it intended that railway guns support all battles in their range? It seems awfully weird that a single gun can support so many battles at the same time and continuously at that. Will there be some limitations placed on that because it certainly isn't a accurate representation of their use and furthermore it seems to me to be open to quite overuse since with but few railway guns one could guarantee a permanent Railway Gun Bombardment penalty for all battles?

Thirdly is there any chance that railway guns would actually use the existing railway on the map to move? From the screens it is clear they act as normal units and I think it wouldn't take much to align them with the rails and it would make it a somewhat more visually appealing animation.

I am also very worried with the range the guns seem to have a range of over 100 km (Ploiesti to Brasov is over around 111km) probably somewhere near 150 km but the scale is hard to get. I don't think any gun in the war ever got anything like that the German K5 had a range of around 86 km but most other guns have a range closer to 50km including the Gustav (bigger doesn't always mean better) so it seems that the ranges of the typical railway guns was also represented in a very odd way that will certainly lead to issues down the line.

I guess part of the representation/balancing issues is offset by the somewhat ridiculous 800 production cost but I can't understand why railway guns are being done this way. Would be a lot better if they were more accurate eg cheaper, unable to aid multiple battles simultaneously but at the same time more of a special use tool that can for example do strategic bombardment on enemy fortifications or infrastructure.

Last why was Gustav used it was just one German crazy wunderwaffe project while they also had railway guns by the dozens so this is like making every German tank into a Maus or something. I mean in total it fired 47 shells in combat over a period of less than two weeks and then spent the rest of the war doing nothing so frankly speaking it is more of a misconception that Gustav was important in the war in any way whatsoever. Any chance of Germany getting a railway gun model that is based on something that actually saw use like say the 28-cm-Kanone 5 (E) which was the most used German model in the war?
 
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I actually heard before that German Railway Guns were fairly effective during the Allied Invasion of Italy.
Makes sense. The other side of the coin works fairly well, too. USS Phoenix (I think, or it was one of the Brooklyns anyway) and some destroyers made a lot of trouble for a German armored division near Salerno (or was it Anzio?).
 
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