[JGRPP] I touch cities and they die

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sjiveru
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[JGRPP] I touch cities and they die

Post by sjiveru »

I'm having an odd experience with the latest JGRPP pack. (I'm posting this here because I don't know if issues with JGRPP that aren't clear bugs are appropriate in the development subforum or not; and also because I don't know how to tell for sure that it's a JGRPP problem.)

This is jgrpp-0.27.1, with the full suite of Japan Set NewGRFs. I'm running with the day length factor set to 5. This game (and all the games I'm sure I've had this problem on) have been custom scenarios with a random sub-arctic map, manual city placement and no industries. (No cities are above the snow line, and none are marked as 'cities', they're all towns technically.)

In short, when I connect a city to my rail network, it quickly begins to shrink. The most visible indicator is my graph of passengers carried per quarter:
passenger volume showing steep drop
passenger volume showing steep drop
openttd jgrpp city death.png (7.99 KiB) Viewed 829 times
The last new line was built in January 1984 with a few minimal capacity upgrades in the rest of 1984; I have done nothing but run the clock since then. Nevertheless, for the last two solid years (December 1984 through December 1986), passenger volume has shrunk quarter-over-quarter. I'm now transporting barely more than half of the passengers I was two years ago.

Looking at the world population, I see that it's at 32,655 as of Jan 1 1987; when I started in 1980 it was 36,398 (and reached a peak somewhere above 37,000 around 1983). The cities I haven't connected have stayed the same; however, the cities I have connected have shown some fairly dramatic drops. The first city I connected, and the largest I've connected yet, started with a population of 2,815 in 1980; seven years later it's fallen to 1,857 (a loss of more than a third of its population!); other cities have fallen similarly (though none quite so extreme) - other early-connected cities fell e.g. 1,702 to 1,425 and 1,285 to 1,047. It seems from looking at my savegames that the drop started sometime around the beginning of 1984. This is despite the fact that these cities claim to be growing at perfectly decent rates. From testing in other games, I've found that if I change the growth rate up to very fast, the large cities still can't even hold steady, while the small towns explode just like you would expect (80 > 500+ over maybe ten years).

This makes for quite a depressing game! Especially seeing as how I have no idea what's causing this. I'm wondering if JGRPP's day length factor is an issue, but I played a long game a few months ago with day length factor 5 and zero problems (though this was likely on an earlier version of JGRPP). Should I downgrade JGRPP? Is there something I'm doing wrong? What's going on?

(I can upload saves if needed.)
Last edited by sjiveru on 04 Nov 2018 10:18, edited 1 time in total.
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Re: [JGRPP] I touch cities and they die

Post by sjiveru »

Sure, here you go! Two saves, same map:

This one is cleaner and a better demonstration of the issue:
Hawthorn & Co., 1st Jan 1987.sav
(65.31 KiB) Downloaded 85 times
Again, the last new line was built in January 1984, and there has been no change to the system at all since sometime in 1984.

This one's been run longer with a larger network, but with a caveat - I built the map for 1980 and then decided I'd like to try it in 1920 instead, and so I changed the date after the cities had been placed. I had thought that this time at least the shrinking was just due to cities replacing large 1980s buildings with small 1920s buildings, but the above save demonstrates that the problem is independent of that issue, so here's that file anyway:
Bigwig & Co., 4th Apr 1935.sav
(106.51 KiB) Downloaded 75 times
Compare the size of cities like Utsunomiya in this one (where I have connected it and it has shrunk) and the above 1980s one (where I haven't connected it and it retains its original size). Note that several cities bottomed out and actually started to grow a bit again in this save - Utsunomiya, for example, fell to something like 1,800 or lower at one point. Also notice Fukui and Himeji, which started too small to shrink, so they so grew normally (modulo the 'very fast' growth setting).

Here's the unbuilt scenario (1980 version):
jp 1980 small clean.scn
(55.67 KiB) Downloaded 83 times
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Re: [JGRPP] I touch cities and they die

Post by Eddi »

NOTE i haven't looked at your savegames, nor have i followed JGRPP development very much.

generally, town growth hits a balance where houses close down at the same speed as new houses get generated.

with certain daylength patches/settings that means, the house generation is slowed down, but the house closure stays at the same speed, so towns might end up at a lower equilibrium. also, GameScripts can affect town growth, but not house lifetime, whereas NewGRFs can affect house lifetime but not town growth. so a mixture of all three may affect your game.

furthermore, towns that are only served by a single station may even grow slower than towns that are not serviced at all. maximum town growth will be at 5 serviced stations. (assuming no GameScript)
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Re: [JGRPP] I touch cities and they die

Post by JGR »

I don't think that this is cause by the day length scaling, as both house demolitions/rebuilds (tile loop) and town growth (town ticks) are scaled by the day length in the same way. Both forms of town growth/shrinkage should occur at the same per-day rate.

I suspect that the problem is that town house demolitions/rebuilds only occur when a town is flagged as growing, however if that actual growth rate is low enough it could be less than the rate of house demolitions.
All of your served towns seem to have growth rates of once every 200 days, which is very slow.

Perhaps town house demolition/rebuild rates also need to be reduced if the town growth rate is low enough, I may look into that at some point.
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Re: [JGRPP] I touch cities and they die

Post by sjiveru »

In short, then, it's ultimately an odd artifact of having one station per town? I.e. the problem should go away if I build bus/tram systems in each town?

(I tried building buses in the 1935 save and the end result was mostly me losing even more money than the shrink alone had caused, but some of that may have been bad network design. I guess it didn't have enough time to take effect?)
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Re: [JGRPP] I touch cities and they die

Post by kamnet »

If you have a train station in each town, then build a bus/mail station attached to it, then build up to 4 other stations of any kind (airports/heliports/seaports also count) within the town limits, run a route. As long as the stations receive regular service, your station ratings will increase, your town rating will increase, and population will recover.
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Re: [JGRPP] I touch cities and they die

Post by NekoMaster »

I almost always serve medium sized towns to large cities with local transit options to bring people to my stations and allow them to get where they want to go
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Re: [JGRPP] I touch cities and they die

Post by sjiveru »

It feels a bit odd to make a bunch of extra overlapping stations when the one train station covers nearly all the town anyway, but I'll try it. I can't bring myself to add more than one or two extra stations in some of these towns, though, just because it seems like any more is purely to work the game mechanics rather than because it seems reasonable otherwise.
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Re: [JGRPP] I touch cities and they die

Post by mak »

Do not need more than one rail station, one rail station and a number of bus stations will suffice.

Set the buses on a circular route in oppossite directions.

Watch the numbers at each station and use extra buses when required, same with trains
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Re: [JGRPP] I touch cities and they die

Post by sjiveru »

I meant that the tram stations still seem like overkill since the train station alone seems to cover most of the city.

I'm still getting some shrink on a city that got a new connection and trams all at once and claims a 77-day growth rate (four stations total). 3200 > 2700 so far.
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Re: [JGRPP] I touch cities and they die

Post by kamnet »

sjiveru wrote:It feels a bit odd to make a bunch of extra overlapping stations when the one train station covers nearly all the town anyway, but I'll try it. I can't bring myself to add more than one or two extra stations in some of these towns, though, just because it seems like any more is purely to work the game mechanics rather than because it seems reasonable otherwise.
Then don't let them overlap. I tend to place my stations in neat grids, with 4 stations aligned in a square and a 5th station in the middle, and I'll run a Figure-8 pattern in both directions to create traffic. The middle station is usually my station where passengers can transfer from one direction to another, and I'll also typically use it to transfer passengers between towns. For small towns, that does mean you're going to be placing stations in areas that have few, if any, buildings. That's okay.
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Re: [JGRPP] I touch cities and they die

Post by sjiveru »

kamnet wrote:
sjiveru wrote:It feels a bit odd to make a bunch of extra overlapping stations when the one train station covers nearly all the town anyway, but I'll try it. I can't bring myself to add more than one or two extra stations in some of these towns, though, just because it seems like any more is purely to work the game mechanics rather than because it seems reasonable otherwise.
Then don't let them overlap. I tend to place my stations in neat grids, with 4 stations aligned in a square and a 5th station in the middle, and I'll run a Figure-8 pattern in both directions to create traffic. The middle station is usually my station where passengers can transfer from one direction to another, and I'll also typically use it to transfer passengers between towns. For small towns, that does mean you're going to be placing stations in areas that have few, if any, buildings. That's okay.
Much of the fun for me in this game is creating a network that seems realistic, not super minmaxed and not designed specifically around game mechanics. Grids of stations, with stations out in the middle of nowhere, really isn't what I'm going for.

Nonetheless, testing seems to show that if I don't have five stations minimum per city, they shrink. Cities with four still shrink.
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Re: [JGRPP] I touch cities and they die

Post by piratescooby »

Trutbourne Transport, 16-08-2086.png
(1.52 MiB) Not downloaded yet
As Long as the towns are well serviced I've no prob on towns shrinking , 1 main rail , bus and truck stop is normally all I use , normally at the centre , moving out to the edges adding a bus/truck network .Connecting to nearest towns , 4/5 in a circular fashion . In this game the towns all require a constant supply of passengers,mail,food and building materials .Try a fresh game , build up a industry network ,foods and the like , pick towns say 5 max and connect with rail and road vehicles , service the towns of what they want .You should see a increase in population .
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Re: [JGRPP] I touch cities and they die

Post by NekoMaster »

sjiveru wrote:It feels a bit odd to make a bunch of extra overlapping stations when the one train station covers nearly all the town anyway, but I'll try it. I can't bring myself to add more than one or two extra stations in some of these towns, though, just because it seems like any more is purely to work the game mechanics rather than because it seems reasonable otherwise.
Some towns and cities IRL do have more then one train station, look at places like Montreal and New York, as well as places that have a lot of commuter/metro trains like what you might get in New york or Japan.

You dont want stations to overlap though as they'll start stealing passengers from each other making them less efficient. Most of the time there are multiple stations in a city they're some distance away, typically the closest they might be in some cases is close enough that one "MIGHT" be able to get off a train and run to the next station a few blocks away and get back on the train at the next station.

While transit might not always be a job for railroads, transport tycoon lets you do what ever you want. You can always imagine that freight and passenger trains are run by your company and commuter trains with other transit options are run by a subsidiary company owned and run by you under the same colors.
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Re: [JGRPP] I touch cities and they die

Post by JGR »

sjiveru wrote:It feels a bit odd to make a bunch of extra overlapping stations when the one train station covers nearly all the town anyway, but I'll try it. I can't bring myself to add more than one or two extra stations in some of these towns, though, just because it seems like any more is purely to work the game mechanics rather than because it seems reasonable otherwise.
sjiveru wrote:
Much of the fun for me in this game is creating a network that seems realistic, not super minmaxed and not designed specifically around game mechanics. Grids of stations, with stations out in the middle of nowhere, really isn't what I'm going for.

Nonetheless, testing seems to show that if I don't have five stations minimum per city, they shrink. Cities with four still shrink.
I agree that it shouldn't have to be necessary to game the mechanism in this way.

Providing a good service should not result in a penalty in the form of shrinking towns, that is a disincentive and non-intuitive.

I am wondering if the old house removal/replacement process should be stopped or halted if the growth rate is below a certain threshold.

It may also be worth looking in the GRF to see if the house age/renewal parameters are sensible.
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Re: [JGRPP] I touch cities and they die

Post by kamnet »

sjiveru wrote:Much of the fun for me in this game is creating a network that seems realistic, not super minmaxed and not designed specifically around game mechanics. Grids of stations, with stations out in the middle of nowhere, really isn't what I'm going for.
I'll agree, creating networks that seem realistic is fun. But the fact is that this isn't how Transport Tycoon Deluxe was designed. It was designed around the game mechanics of moving stuff from one point to another point in order to score points and win the game. I'm very much a sandbox player who plays mostly for aesthetics, but sometimes you have to respect the game in order to achieve your goals.

Unless somebody manages to find a way to work around that core programming. Maybe JGR's suggestions will help guide the way.
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Re: [JGRPP] I touch cities and they die

Post by sjiveru »

JGR wrote:I am wondering if the old house removal/replacement process should be stopped or halted if the growth rate is below a certain threshold.

It may also be worth looking in the GRF to see if the house age/renewal parameters are sensible.
This seems to me to be the best solution. It would make most intuitive sense to make the removal rate proportional to the growth rate, though I don't know if that would work in practice.

I don't know much about the internals of GRFs, but I'm using the Japan Set's town GRF, and I suppose it might well have odd parameters set. I wouldn't know how to check or tell, though.
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Re: [JGRPP] I touch cities and they die

Post by sjiveru »

Welp, it's not the GRF and it's not the day length setting - day length 1 just results in proportionally faster shrink, and it still happens with the default towns. Anyone have any good short-term solutions short of gamey station placement? (I'm not even convinced that that works; I've seen shrink on a 32-day growth cycle city with 'faster growth rate' on.)
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Re: [JGRPP] I touch cities and they die

Post by Eddi »

i'm sorry that the game mechanics don't agree with your play style, but there's little else to say about it.

except that you can use the "fund new buildings" town interaction to supercharge town growth temporarily

or you can use a game script that changes the way town growth works.
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