• We have updated our Community Code of Conduct. Please read through the new rules for the forum that are an integral part of Paradox Interactive’s User Agreement.

HOI4 Dev Diary - Traiiiiins

Greetings, and welcome back for our last look at the supply system that ships with the Barbarossa update. As you all know, I’m British, and in Britain the trains never run on time - I couldn’t possibly break with this tradition, hence a completely intentional 10 minute delay on today’s diary.

There’ve been a couple of changes since we last looked at this, so you may find I’ll be reiterating a few aspects that we’ve already covered in previous diaries, albeit in some cases with a new twist.

Trains

As indicated in a previous diary, the logistics network that supplies your troops relies on the large-scale relocation of supply using trucks and trains.

Whereas trucks serve as an optional last-mile carrier for military supplies, trains make up the backbone of any logistics network that supplies an army which exceeds the local state supply available in its location.

The domestic production of trains is something that is unlocked via the technology tree. Many countries will start with the initial (civilian) train technology readily unlocked, however, there are several more options available to you as time progresses (more on this below!).

0.png


Your overall train need for the logistics network is derived from the overall supply usage of the nodes supplying your troops, and the distance factor that supply has to travel in order to reach them. In essence, the more troops you have drawing supply, the more trains you will need to keep supply running.

Needless to say, if fewer trains are provided than are required, supply output at point of demand will incur penalties proportional to the magnitude of the shortfall.

In one of our previous diaries, we alluded to a number of interactions that could be performed on supply nodes - one of these was a train priority setting. It transpired that this did not fit well with the underlying simulation, and we’ve removed this setting from nodes.

Logistics Strike

Of course, a freight-train loaded with supply makes a juicy target for the enemy. In NSB, CAS and bombers are able to perform the new logistics strike mission, which can put a severe strain on an enemy’s ability to supply their network - actively destroying trains and trucks, as well as damaging railways in the target area.

The strategic bombing air mission will also target rail and supply infrastructure, however the logistics strike mission is a much more effective way of neutralizing an enemy’s fighting capabilities while retaining important industrial infrastructure if you intend to occupy an area for any period of time.


1.png


Train Variants

As mentioned above, trains will be a researchable technology with several variants. Trains, unlike regular units, are not controllable - their movement and behaviour is entirely simulated based on the needs of your logistics flow. This said, there are several important statistical aspects to them.

2.png


To begin with, most of your network is likely to be populated by civilian trains. You can construct more of these by co-opting military factories. Further on in your campaign, you can unlock a variant of the civilian train with a significantly reduced construction cost.

To combat the strategic mission mentioned above, there is one (or..is it more?) further item in your toolbox for owners of the NSB expansion. Armored trains, while coming with a higher price tag, are much more resistant to destruction from air missions, and can act as an effective deterrent against logistics disruption.

Train enthusiasts (we have none of those here, right?) will note that the trains displayed above belong to the soviet union - there is indeed unique art as well as 3d models for several other major nations.

3.png


4.png


5.png


6.png

A highly camouflaged train in action.

7.png

Displayed trains are based on your stockpiled train equipment. This is the german armoured locomotive!

That’s all from me for today - I’ll hand over here to @YaBoy_Bobby to go over some of the details on supply distribution at a hub level:

Hub to Province Supply Distribution

We have talked about how trains and rails feed the supply hubs, but not so much about how hubs feed divisions in the field. As hubs are fed from the capital province by a rail network, divisions are fed by hubs over land.

Every Hub has an overland range that gives it a collection of provinces that it touches. This range is constant, but the cost of moving over each province is impacted by things like weather, terrain, rivers, and infrastructure. Motorization decreases the penalty for crossing each province, thus increasing the number of provinces a hub will touch and potentially creating greater hub density and thus greater overall supply in an area.

8.png


As has been alluded to with the phrase “hub density,” a province may be touched by multiple hubs. When multiple hubs touch a province, a ratio is created to determine what percentage of the supply requested each hub is responsible for. Every hub that touches a province lessens the supply burden of other hubs also touching the province.

In the final step, Divisions draw supply from hubs, depending upon the relationship between their current province and the hubs that touch that province. When a hub does not have enough supply to meet demands, the lack of supply is distributed evenly across all divisions currently drawing from the hub.

In older DDs we talked about a penalty to the amount of supply delivered to a province based upon weather, terrain, and distance. Over the summer we decided to remove this penalty as we found it compounded in a hard to predict way that created bad supply and sometimes penalized having more hubs touching a province in a way that we did not like.
 
  • 173Like
  • 77Love
  • 17
  • 5
  • 2
Reactions:
I know, was just joking at the idea of producing horses.

Being serious the game doesn't need to reach that level of detail. While Germany and other countries often suffered to replace lost horses that economy is not well represented with the economy the game currently uses.

Horses are not produced in factories and unlike resources like Rubber or Oil the current number of animals available to adquire was much more limited.
It could be represented by with horsepower, in parallel with manpower. We’d probably have to wait for modders though. I wished horse supply wasn’t the lowest, because using horses still required a significant investment of resources.
 
To begin with, most of your network is likely to be populated by civilian trains. You can construct more of these by co-opting military factories. Further on in your campaign, you can unlock a variant of the civilian train with a significantly reduced construction cost.


I'm assuming from this comment that a nation's economy will passive produce a trickle of civilian trains by default, sorta like how fuel slowly accumulates even without domestic oil production. If so, then I would only need to devote military factories to the job when I want to bump up my logistics capacity quickly. Is that correct?

Otherwise, I'm worried about smaller nations that start off with a decent civilian economy, but very few mils (Australia, Portugal, etc.). I was thinking Civs would produce some amount of logistical equipment by default, without having to devote a military factory. It feels like factories spent on Consumer Goods should produce a few trucks and trains, simply to get those consumer goods to market.
 
  • 3Like
  • 1
Reactions:
In one of our previous diaries, we alluded to a number of interactions that could be performed on supply nodes - one of these was a train priority setting. It transpired that this did not fit well with the underlying simulation, and we’ve removed this setting from nodes.

I applaud the design choice of "simpler is better". Would hope that some of those freed up manpower hours are assigned to addressing "bugs".

Ammunition is represented by attrition of equipment. Supplies only covers food, water, clothing, etc. for your troops.
I would hope the comment about ammunition is wrong. Otherwise, the unit supply values are seriously off.


Horse Production
manpower pool.
horsepower pool and unit value for horses.

If we get a horsepower pool, we can correctly reflect the use of horses. For now, should be abstracted into support equipment.

Armored Trains
Would have to assume, they would cause damage to attacking air (CAS, TAC) on Logistic strike missions. If not, please consider.

that the supply trucks used by the hubs do not consume fuel.
Another requesting if this is true, please reconsider. If they can die for their country, they should be allowed to drink. :)
 
  • 4
  • 3Like
  • 2
Reactions:
Yes! Do this, but Italian trains carry less supply due to putting the focus on being on time instead of carrying a full load!
No actually. The thing about Mussolini "making the trains run on time" is that he didnt. At no point did he really succeed at making them run faster. What he actually did was have the train schedule adjusted so that the schedule arrival time was the time the trains were usually late by. Innother words, he half-assed it and just declared the delays as being "on-time" instead of actually trying to get the trains to meet it.
Hi Arheo!

Right now the AI use air wings spam to bomb the player way way behind enemy lines with no restiction (ex: england/russia bomb central germany constantly) and there is little that the players can do to stop them 100%.
How are you going to prevent this behaviour with the logistick strikes?
Um....welcome to being Germany during WW2. That was something Germany had to face constantly during WW2 and they were never able to stop them even 50%. I see no reason for why the devs should make the AI not make you have to defend German Airspace. If you are having issues and cant spare more fighters, build more static AA and never used concentrated industry, and defeat Russia, so you can actually focus your aircraft on the west.
 
  • 5Like
Reactions:
If you have both armored and civilian trains, what determines which trains are hit by enemy bombers?

For example, if your country has 50%armored trains and 50% civilians, will it be modelled as if the armored trains are assigned to the "dangerous routes" and the civilian trains to the "safe routes" so as long as you have sufficient armored trains for the dangerous routes, it's always the stats of armored trains that apply?
 
  • 1Like
Reactions:
Um....welcome to being Germany during WW2. That was something Germany had to face constantly during WW2 and they were never able to stop them even 50%. I see no reason for why the devs should make the AI not make you have to defend German Airspace. If you are having issues and cant spare more fighters, build more static AA and never used concentrated industry, and defeat Russia, so you can actually focus your aircraft on the west.
Good point. But casual players will argue that bombers teleporting is a broken mechanic even more now that the AI doing air bomber spam gives the AI an effective tactic.
 
  • 1Like
  • 1
Reactions:
Can you cut off the access to Resources if you cut the Railway Lines going there?
Like removing Soviet access to their oilfields by capturing vital railway lines.
 
  • 2Like
  • 2
Reactions:
  • 5
  • 2Like
Reactions:
When will we see a map of the network?
 
I'm assuming from this comment that a nation's economy will passive produce a trickle of civilian trains by default, sorta like how fuel slowly accumulates even without domestic oil production. If so, then I would only need to devote military factories to the job when I want to bump up my logistics capacity quickly. Is that correct?

Otherwise, I'm worried about smaller nations that start off with a decent civilian economy, but very few mils (Australia, Portugal, etc.). I was thinking Civs would produce some amount of logistical equipment by default, without having to devote a military factory. It feels like factories spent on Consumer Goods should produce a few trucks and trains, simply to get those consumer goods to market.
No. Countries starts with some trains, depending on its size. The amount of trains needed obviously scales with the amount of units you field and the size of the front you fight on. I recently did an Australia playthrough and if you plan ahead it is totally manageable. It becomes a problem if you ignore it or someone bombs them and you suddenly need to produce vast quantities of trains in a short timeframe

*cough stuck in Siberia cough*

Its a big issue if you are stuck without trains in lower infra areas of the world (Middle east, Parts of Russia, China (most of Asia in fact), South America etc)
 
  • 22Like
  • 14
  • 1Love
Reactions:
I think it is very bad news that not being able to prioritize the different hubs according to our convenience and an important step back to the depth of the new logistics system that is one of the great assets of this dlc.

I think it can be implemented in some way that the vital role that horse transport had for many nations even for nations as relevant as the USSR or Germany, which was a mostly Hippomovil army during WWII
 
  • 5
  • 3Like
  • 1Haha
Reactions:
Will the update replicate the different track gauges around the world, such as the narrow gauge lines in sub-Saharan Africa , South East Asia, and South America; and the broad gauge lines in India, Russia, and Spain?
 
  • 1Like
  • 1
Reactions:
Oh boy, looks like at last I can do my alt hist for my country:

-Native Tank models? check
-A better military academy than at the time? check
-Have trains and a functional railroad network during wartime? check

Say, what's the ETA for the teaser of the ETA of the announcement of the ETA of the trailer that gives the release date of NSB?
 
and the USSR in 36 for comparison (note the use of the river in the north)
Will there be any scripted/historical or buildable addons to the railway-system? I note for example that Saratov on the Volga seems like a dead-end on the screenshot and that the Volga Railroad isn't a "thing" at the moment of the screenshot.
 
  • 1Like
Reactions: