What causes a town to shrink?

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What causes a town to shrink?

Post by Redirect Left »

I'm currently playing a large map, however i'm noticing many of the larger towns/cities have now started to shrink.
I've checked out the wiki to try finding out why, however the wiki only details how to make them grow, it doesn't seem to go into detail of why they may shrink. (Wiki page on towns)

So basically, can anyone detail the reasons a town may start to shrink? It removes the houses and stuff around the edges, however leaves the road network intact.

thanks in advance for any replies :wink:
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Re: What causes a town to shrink?

Post by FooBar »

This can happen if newly built houses have a significant higher population than old houses, if I'm not mistaken. E.g. you have a town of 10 houses with population 4. The next growth stage the town wants to increase its population from 40 to 44, but it can only build new houses with population 12. To do this, it has to add one house with population 12, but also remove two houses with population 4.
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Re: What causes a town to shrink?

Post by Redirect Left »

Hmmm, but that wouldn't cause the population to shrink too though, right? If it was replacing the smaller houses with bigger ones?
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Re: What causes a town to shrink?

Post by Transportman »

If I remember correctly, the town shrinks because the building rate of new houses is slower than the decaying of old houses. Once you get some transportation going, it will grow again.

If it is what FooBar describes, it is just a temporary dip because the old house is already removed, but nobody is in the new house because it is under construction.

Look at the town windows to see what it is, it should indicate whether the town is growing or not.
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Re: What causes a town to shrink?

Post by Redirect Left »

Transportman wrote: Look at the town windows to see what it is, it should indicate whether the town is growing or not.
I've done so, they say "Town is not growing". However there has been no change in the local transport network that affects how many trains go by it. So i'm out of ideas. Unless its just reached its max, then decided to shrink instead of sticking?
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Re: What causes a town to shrink?

Post by siu238X »

A savegame post will always help in this case...
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Re: What causes a town to shrink?

Post by YNM »

I also notice this several times in a game.

Most of the time, a larger city shrunk while the next city on the service (Or the next largest city on the service, if using CargoDist) expand. I don't know exactly whats causing this, but i think its still quite make sense - (trans)migration of people from one city to another one. Well, this does make problem quite much, but as the shrunken and enlarged city are connected, on passenger number it won't make noticeable sense on profits.

The only way out is : stop the goods flowing to the enlarged city and move it to the shrunken city. Big city cases mostly don't have large impacts on cargo acceptance. That way, it will reverse the "migration" flow. or just supply them both for better result.
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Re: What causes a town to shrink?

Post by Pyoro »

I'd probably check the road-layout first; remove dead-ends and unnecessary roads and check that the center is properly connected. Also iirc changing the road-layout towns use will also affect town growth as they've different growth rates, so even if the roads didn't change it might cause a town to shrink...
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Re: What causes a town to shrink?

Post by YNM »

Pyoro wrote:I'd probably check the road-layout first; remove dead-ends and unnecessary roads and check that the center is properly connected. Also iirc changing the road-layout towns use will also affect town growth as they've different growth rates, so even if the roads didn't change it might cause a town to shrink...
Meh, no effects here :) (as if the towns actually can't build more buildings, it'll expand by build more taller and larger buildings - a good thing actually.)

But well, removing dead-ends and unnecessary roads is indeed a must, if you want to see your city evetually exceeding 10,000 population :o
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Re: What causes a town to shrink?

Post by andythenorth »

What year are you playing? If post 1930, ignore the following comments.

Pre-1930 towns / cities may well shrink if serviced. This is not wholly deterministic, but does happen quite frequently.

This is not by design, but is a side effect of the building types available to towns for those dates in the default game. Typically you'll notice issues like large blocks of flats being replaced by smaller houses, but more commonly you'll end up with a town that is mostly theatres.

It's not considered a bug by any of the openttd developers I've mentioned it to.

Whatever date you're playing, I'd recommend trying TAI for niceness, or NA City Set if you want very large passenger numbers.
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Re: What causes a town to shrink?

Post by bjgttd »

andythenorth wrote:I'd recommend trying TAI for niceness, or NA City Set if you want very large passenger numbers
According to GRFCrawler the NACity became CanCity, but the download link requires registration. I also can't find it on BaNaNaS. Is there a place I can download it?
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Re: What causes a town to shrink?

Post by FooBar »

You can find a version of it in the #openttdcoop grf pack: http://wiki.openttdcoop.org/GRF
I believe the current CanCity is just a renamed NACity, without any new features. So you might just as well take the older version.
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Re: What causes a town to shrink?

Post by bjgttd »

FooBar wrote:You can find a version of it in the #openttdcoop grf pack: http://wiki.openttdcoop.org/GRF
I believe the current CanCity is just a renamed NACity, without any new features. So you might just as well take the older version.
The version there is 0.1 from 2008, the current one is 1.1 from 2012 - it's really unlikely they are the same.
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Re: What causes a town to shrink?

Post by mfb »

FooBar wrote:This can happen if newly built houses have a significant higher population than old houses, if I'm not mistaken. E.g. you have a town of 10 houses with population 4. The next growth stage the town wants to increase its population from 40 to 44, but it can only build new houses with population 12. To do this, it has to add one house with population 12, but also remove two houses with population 4.
Sorry, but this is completely wrong. The town does not care about its population at all - just the house number is important for all town actions. Towns do not decide "hey, I'll kill this building for whatever reason" - buildings just die after a while, this is independent of town growth.
Jolteon wrote:I've done so, they say "Town is not growing".
In this case, you do not have active stations close to the city center (where "close" depends on the city size itself, ~50% larger than the region with sidewalks on the roads), have town growth disabled or do not supply food/water if required. If you use certain NewGRFs, there can be additional requirements.
Houses vanish after a while (~80 years without NewGRFs) - the only way to keep the town size constant is to ensure that enough new houses will be built.
Yoursnotmine wrote: (as if the towns actually can't build more buildings, it'll expand by build more taller and larger buildings - a good thing actually.)
Only if there are free spots for those buildings - with a proper road design, those spots are rare, so it does not help to constrain the town size.


Probably more about towns than you need ;).
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Re: What causes a town to shrink?

Post by Redirect Left »

Hmm. I just thought.

Could this be related to me doing a few little cheats in the placement of rail stations? I often place them on the outskirts of towns, and then use the ctrl+click method to link bus stops in the town center to the rail station? I do this cause I hate destroying half of the town to place a station, so do it on the outskirts with linking bus stops in the town. Is this perhaps making towns think the station is miles away and then deciding "Wait no, enough of this cheating" and shrinking instead? :p

I'm not using any GRFs that affect how towns grow, and i'm playing on temperate, which i believe needs nothing but any sort of passenger/goods transport to grow.
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Re: What causes a town to shrink?

Post by Supercheese »

Jolteon wrote:Hmm. I just thought.

Could this be related to me doing a few little cheats in the placement of rail stations? I often place them on the outskirts of towns, and then use the ctrl+click method to link bus stops in the town center to the rail station? I do this cause I hate destroying half of the town to place a station, so do it on the outskirts with linking bus stops in the town. Is this perhaps making towns think the station is miles away and then deciding "Wait no, enough of this cheating" and shrinking instead? :p

I'm not using any GRFs that affect how towns grow, and i'm playing on temperate, which i believe needs nothing but any sort of passenger/goods transport to grow.
It would be better to do it the other way around, to place the station tiles in the center of the city first, and then place the station on the outskirts. That way the station sign is near the city and it counts for growth.
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Re: What causes a town to shrink?

Post by FooBar »

bjgttd wrote:
FooBar wrote:You can find a version of it in the #openttdcoop grf pack: http://wiki.openttdcoop.org/GRF
I believe the current CanCity is just a renamed NACity, without any new features. So you might just as well take the older version.
The version there is 0.1 from 2008, the current one is 1.1 from 2012 - it's really unlikely they are the same.
Then register at the simuscape website and get the most recent version from there ;)
mfb wrote:Sorry, but this is completely wrong. The town does not care about its population at all - just the house number is important for all town actions. Towns do not decide "hey, I'll kill this building for whatever reason" - buildings just die after a while, this is independent of town growth.
Thanks for explaining. If you don't mind I've added a link to your article to the Towns page on the openttd wiki.
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Re: What causes a town to shrink?

Post by bjgttd »

FooBar wrote:
bjgttd wrote:
FooBar wrote:You can find a version of it in the #openttdcoop grf pack: http://wiki.openttdcoop.org/GRF
I believe the current CanCity is just a renamed NACity, without any new features. So you might just as well take the older version.
The version there is 0.1 from 2008, the current one is 1.1 from 2012 - it's really unlikely they are the same.
Then register at the simuscape website and get the most recent version from there ;)
I have. Strange people. Probably have their reasons.
It appears that the only (declared) difference is the population parameter. It's 20% less than before by default and can be changed from 0 to 200%.
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