• 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've always found it kind of weird how a silent peaceful front would consume the same ammount of supplies of an active front, unlike how it works with the fuel mechanic which is only drained when the unit is moving or fighting. Will this be touched at all in the DLC? I haven't seen all the dev diaries.
I like the way you think!

In the current game, supply can be prioritized by theater/front.
Is this implemented in the DLC, too? It would be rather useless to have trains go all over the country, but not where I would like to see the main effort of my forces.
Can trains be specifically assigned to armies/army groups, such as transport planes? Can I assign newer (armored) trains to specific areas/units, and older ones to less important areas?
 
  • 1Like
Reactions:
I'm really disappointed by the slow pace of NSB development so far.:(

You guys annouced that update way to early or you progress very slowly.

TfV 1st annoucement untill release >>> 83 days
DoD 1st annoucement untill release >>> 63 days
WtT 1st annoucement untill release >>> 176 days
MtG 1st annoucement untill release >>> 281 days
LaR 1st annoucement untill release >>> 188 days

NSB 1st annoucement untill now >>> 153 days
This time we got no release nor even a world war wednesday in sight and most of the content you showed us are focus trees.
Some of the stuff you showed us prior you even cancelled today.
I prefer this over a buggy product - keep doing what you are doing guys, it's going to be good!
 
  • 6Like
  • 3
Reactions:
This pleases me. So much so, that I wouldn't be opposed to a cosmetic DLC revolving around trains and how they appear in-game. Why, you might ask? Because then I could see THIS:

https://www.grovercorp.com/wp-content/uploads/2019/10/SP-4449.jpg

@Axe99 Southern Pacific #4449, The Daylight. The most famous locomotive in the United States, often called the most beautiful ever built, and my personal favorite in the world. Commissioned as part of the fourth class of GS (Gold State, for California) locomotives, all intended as part of a stimulus to ease the Great Depression's effect on California, she and her sisters performed passenger and freight service for decades, with the most popular being the coastal routes. During World War II, they had the job of transporting soldiers and supplies to the ports. Due to material rationing, the last GS-class lacked the prominent streamlined side skirts, and were only painted black. Of the GS-6s, only one remains today: 4460.

1630535230786.png
The 4449 was the only Daylight locomotive to be saved during dieselization, painted black and moved to Oak's Park in Portland, Oregon in the 1950s. There she remained, never to run again... until 1976. To celebrate America's Bicentennial, the railroads ran a second American Freedom Train, the first having come shortly after the war. When the time came to find a locomotive, all eyes fell on the 4449. Worn from weather and vandalized, she underwent a massive overhaul to get her ready, finished off with a red, white, and blue paintjob. Starting from Delaware, she traveled to each of the 48 contiguous states, carrying items like the Liberty Bell and the Lunar Rover. In doing so, they combined my three favorite things: trains, history, and America.
1630535461611.png
She remains in working order to this day, often pulling excursion trains and even appearing in movies, including my favorite of all: Tough Guys, starring Burt Lancaster and Kirk Douglas. I recommend it to anyone looking for a good laugh with some of the best actors we've had.
 
Last edited:
  • 4Like
  • 2Haha
  • 1Love
  • 1
Reactions:
This pleases me. So much so, that I wouldn't be opposed to a cosmetic DLC revolving around trains and how they appear in-game. Why, you might ask? Because then I could see THIS:

https://www.grovercorp.com/wp-content/uploads/2019/10/SP-4449.jpg

@Axe99 Southern Pacific #4449, The Daylight. The most famous locomotive in the United States, often called the most beautiful ever built, and my personal favorite in the world. Commissioned as part of the fourth class of GS (Gold State, for California) locomotives, all intended as part of a stimulus to ease the Great Depression's effect on California, she and her sisters performed passenger and freight service for decades, with the most popular being the seaside run. During World War II, they had the job of transporting soldiers and supplies to the ports. Due to material rationing, the last GS-class lacked the prominent streamlined side skirts, and were only painted black. Of the GS-6s, only one remains today: 4460.

The 4449 was the only Daylight locomotive to be saved during dieselization, painted black and moved to Oak's Park in Portland, Oregon in the 1950s. There she remained, never to run again... until 1976. To celebrate America's Bicentennial, the railroads ran a second American Freedom Train, the first having come shortly after the war. When the time came to find a locomotive, all eyes fell on the 4449. Worn from weather and vandalized, she underwent a massive overhaul to get her ready, finished off with a red, white, and blue paintjob. Starting from Delaware, she traveled to each of the 48 contiguous states, carrying items like the Liberty Bell and the Lunar Rover. In doing so, they combined my three favorite things: trains, history, and America.
She remains in working order to this day, often pulling excursion trains and even appearing in movies, including my favorite of all: Tough Guys, starring Burt Lancaster and Kirk Douglas. I recommend it to anyone looking for a good laugh with some of the best actors we've had.
Those bright colors are primary marks for transatlantic bombers!

;)
 
  • 1Like
Reactions:
soooo, how screwed are nations like china that dont have the industry to spare to make more trains and trucks.....but field huge armies?
Not the size of the army that matters. It is the amount of supplies it draws.
 
  • 5Like
  • 1
Reactions:
What about the country-specific differences?

When Germany invaded the USSR, the railway system provided several problems.

- Different gauges (which means that the Germans had to spend time and resources before they could use the Soviet tracks)
- Different ranges (Soviet steam locomotives had a longer range)
- Different weather (German locomotives were not constructed for extremely cold conditions).

So, will there be some malus for Germany using Soviet tracks?
The different gauges could mean that newly captured Soviet track can't be used immediately.
And maybe a specialization for long-range/all-weather locomotives?
With shorter-ranged ones suffering a malus in the USSR and "summer locomotives" being less efficient in Soviet winters?

Furthermore, I hope that trains can be lend leased.

In real life, the US lend-leased a lot of rolling stock to the USSR.

I am really looking forward to NSB....rail usage could be as important as the introduction of fuel in MTG!
 
  • 4Like
Reactions:
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
The devs have already stated that horses are represented by being able to transport supplies from a hub even without trucks
 
  • 3Like
Reactions:
Hopefully it is possible to sabotage your own infrastructure which is what happened on the Eastern Front especially at a very large scale. It should probably require a Division to physically be in the province and take some time to do.

Also I believe Armored Trains were used by the Germans in anti-partisan warfare. At least inside the USSR.

Heavy Fighters should probably be able to do the Logistics Strike mission. Pretty sure they did that in real life.

Also, please add Bocage terrain to Northern France. As a new terrain or modifier on the correct provinces.

And make it possible to reduce Urban provinces to rubble after prolonged fighting/bombing so we can recreate our own Stalingrad. A destroyed city would become a highly defensible location for a defending army.

I AM worried about how the game is going to represent railroad conversion. Because most nations in Europe (and probably the world) DID use the same railroad gauge. It was only a few outliers like the USSR/Spain that used a different wider gauge. This is something that should be represented as a National Spirit maybe. Or should only be triggered if a standard gauge country like Germany invades a wide gauge country like the USSR.

The Germans not only had to convert the Soviet rail lines they also had to build many more Stations because German trains didn't carry as much fuel/as high quality fuel as Soviet trains so their range was lower. The Germans were hoping to capture large numbers of Soviet rolling stock/trains so they could use them and wouldn't have to convert as much railroad. However, they were unable to capture enough Soviet trains/rolling stock (Soviets retreated or destroyed them) so in the end the Germans had to convert tens of thousands of Soviet railroads to the German standard gauge which was a huge effort in manpower and time.

Another big problem the Germans ran into when invading the USSR is that most Soviet rail lines led to Moscow. However, this is not necessarily where the German invasion routes were going.

FYI, I think when the Soviets invaded the Baltic states they had to convert their standard gauge to Soviet wide gauge.

Regarding Trucks. One of the big problems the Germans had is that they never had enough Trucks to supply their armies. Which made them very reliant on the railroads. They had to confiscate many Trucks from the local populations and conquered countries. And this led to the very bad situation of having like 2,000 different types of Trucks in service which was a logistical nightmare. Will this be modeled at all? Maybe a National Spirit?

Also, are Rail lines going to have a capacity limit finally? It's always been way too easy to strategically redeploy armies in HOI4.

Regarding Armored Trains. The Poles used them effectively in the defense of their country against German ground forces until they were destroyed by the Luftwaffe. The Germans tried to use their own against the Poles when attacking rail bridges but they were ineffective because the Poles blew up bridges. Later the Germans used Armored Trains to protect their supply lines against Soviet partisans. So Armored Trains should definitely have a role in ground combat.

German Rail Conversion: https://history.stackexchange.com/q...-about-the-different-rail-gauge-in-the-soviet










railway-gauges-europe.jpg


Note: I do not know if this map is accurate for the World War 2 time period. It is probably mostly accurate I would guess.
 
  • 9Like
  • 2
Reactions:
Hopefully it is possible to sabotage your own infrastructure which is what happened on the Eastern Front especially at a very large scale. It should probably require a Division to physically be in the province and take some time to do.

IIRC already in the game, I think. I believe the Soviet Union already gets a few decisions to do scorched earth if Germany takes certain territory, which heavily damages infrastructure.
 
  • 3
Reactions:
Hopefully it is possible to sabotage your own infrastructure which is what happened on the Eastern Front especially at a very large scale. It should probably require a Division to physically be in the province and take some time to do.

Also I believe Armored Trains were used by the Germans in anti-partisan warfare. At least inside the USSR.

Heavy Fighters should probably be able to do the Logistics Strike mission. Pretty sure they did that in real life.

Also, please add Bocage terrain to Northern France. As a new terrain or modifier on the correct provinces.

And make it possible to reduce Urban provinces to rubble after prolonged fighting/bombing so we can recreate our own Stalingrad. A destroyed city would become a highly defensible location for a defending army.

I AM worried about how the game is going to represent railroad conversion. Because most nations in Europe (and probably the world) DID use the same railroad gauge. It was only a few outliers like the USSR/Spain that used a different wider gauge. This is something that should be represented as a National Spirit maybe. Or should only be triggered if a standard gauge country like Germany invades a wide gauge country like the USSR.

The Germans not only had to convert the Soviet rail lines they also had to build many more Stations because German trains didn't carry as much fuel/as high quality fuel as Soviet trains so their range was lower. The Germans were hoping to capture large numbers of Soviet rolling stock/trains so they could use them and wouldn't have to convert as much railroad. However, they were unable to capture enough Soviet trains/rolling stock (Soviets retreated or destroyed them) so in the end the Germans had to convert tens of thousands of Soviet railroads to the German standard gauge which was a huge effort in manpower and time.

Another big problem the Germans ran into when invading the USSR is that most Soviet rail lines led to Moscow. However, this is not necessarily where the German invasion routes were going.

FYI, I think when the Soviets invaded the Baltic states they had to convert their standard gauge to Soviet wide gauge.

Regarding Trucks. One of the big problems the Germans had is that they never had enough Trucks to supply their armies. Which made them very reliant on the railroads. They had to confiscate many Trucks from the local populations and conquered countries. And this led to the very bad situation of having like 2,000 different types of Trucks in service which was a logistical nightmare. Will this be modeled at all? Maybe a National Spirit?

Also, are Rail lines going to have a capacity limit finally? It's always been way too easy to strategically redeploy armies in HOI4.

Regarding Armored Trains. The Poles used them effectively in the defense of their country against German ground forces until they were destroyed by the Luftwaffe. The Germans tried to use their own against the Poles when attacking rail bridges but they were ineffective because the Poles blew up bridges. Later the Germans used Armored Trains to protect their supply lines against Soviet partisans. So Armored Trains should definitely have a role in ground combat.

German Rail Conversion: https://history.stackexchange.com/q...-about-the-different-rail-gauge-in-the-soviet










View attachment 752655

Note: I do not know if this map is accurate for the World War 2 time period. It is probably mostly accurate I would guess.
I do remember they changed the gauges at the end of WWII, and that there exist rails that cover multiple gauges. Otherwise, they can just switch trains at a depot.