[brian51]

yes, I know Pierre has always been one of the strongest Mass transit players I ever met in sc-4

Ive known this for many years now

[pierreh]

In my initial post in this CJ I illustrated, among other things, the triple direct subway connection between Arcens and Cherenne, running in a corner of Deramey.

That triple connection continues to be a source of concern, for various reasons. For one thing, since it involves 3 cities, including the middle one (Deramey) that plays a totally passive role in the connection but still has to carry the traffic, it is very difficult to get the traffic figures to balance between the 2 cities at each end of the connection. I have actually more or less given up on the task of getting figures to converge.

The respective traffic figures, measured in the middle city (Deramey), haven't changed much and the respective loads are still quite unbalanced:




In Cherenne, in an attempt to get more usage of the middle subway connection, I implemented a tunnel junction (circled in red)  that, in actual practice, would be a no-no in any subway system with tight frequencies of trains:



It is worth noting that the traffic figure of the middle connection (18528) matches exactly the one measured in Deramey, whereas the figures of the other 2 connections vary a lot.

The cities will be played further and the situation monitored. I'll show later the Arcens side, where currently the left-most connection shows total saturation (65535).

[Darth-Apple]

It seems that SC4 is using a pretty simplistic algorithm to determine the routes that get used. It seems surprising, but with the game running on a single core... well... I wish they had made this game 5 years later!

Do you find that if the routes are maybe slightly different (e.g. maybe a single-station difference on each one) that it might recalculate the routes that are used and balance them out a bit more? My subways were never this popular in my cities.

Nice updates as always. Thank you for posting!

[brian51]

Pierre,

thanks for your latest CJ posting !

I have experienced similar frustrations trying to get neighbor connections to balance out  with traffic figure amounts..
However it is interesting ( but certainly odd), that the 2 outer tubes did show more balance now, even though you were trying to effect the middle tube , which as you pointed out unchanged.. I think the best try for me, was always to use the smaller connecting cross- tubes between main lines... As you have already illustrated the effects of constructing the first one of these..

[pierreh]

This is a continuation of my observations and musings about subway inter-city connections, and more specifically about the triple connection between Arcens and Cherenne, passing thru Deramey.


The first picture in this post shows the zoning in Cherenne. As is the case in other cities, I didn't pay attention to the respective locations of the zones, in order to ensure that inter-city traffic would remain moderate. The Sims in the northern residential areas and in the central western area can find work in the commercial zone; those in the southwest residential area will prefer to look for work at the southern border (border to Deramey):



In Cherenne the 3 subway tunnels originate in the residential zone in the southwest corner of the city. Like other residential areas it is zoned with high density and features several high-rises:



The traffic volume view for mass transit (GLR and subway) in that area looks like this:



The next picture is rotated by 90 degrees to show a section of an avenue where GLR tracks branch off from the center of the avenue to move to the side and enter a subway tunnel - that tunnel becomes the second (middle) inter-city subway connector:



Circled in red is a GLR track layout intended to 'capture' some of the GLR traffic into the subway tunnel, before the traffic circle on the right of the picture where other GLR tracks arrive. So far it doesn't work as well as I would like, that is, it does not divert enough traffic, as can be seen here:



If we look at the paths leading to the busiest of the 3 subway links, we can see that their origins are nearly exclusively in residential buildings in the area. The traffic simulator is sending all those Sims 'on the other side of the border' to find work there:





Now we take a look at the other end of the link, in Arcens. Because of the already mentioned difficulty to get traffic figures to jive, especially in the 3-cities setup illustrated here, the numbers are different, and the first link is saturated. Here are the surface and the subway views of the area:





The second view shows the rather complex array of subway tunnels and GLR tracks with transitions. The middle link terminates at a train station. The rightmost link arrives into a GLR+subway combo station of which all 4 tiles are occupied by tunnels.

The leftmost link, the one that is saturated, ends with a subway-to-GLR transition that is immediately adjacent to a 'grand union' GLR intersection. The GLR tracks going toward the train station are very close to saturation:



This specific arrangement is not satisfying, and should be improved, even in the case where it is possible to reduce the congestion by a better balancing of the loads. Because the area is rather cramped with railway tracks, roads and buildings, making things better there is quite a challenge.

[brian51]

Pierre,

your CJ updates are so amazing , as compared to my small ones.... they leave me speechless really !

The majority of them have so many great images like this one.. I really like the high rise pic of your city a lot, because it shows what beautiful cities you build..
Of course, beautiful to us is dense urban cities with very high populations usually.. But this is how we like to play sc4

Also one aspect we both love in sc4 is Traffic..
and you of course manage it as well as anyone i know ..

It is also of interest to me most of your recent postings have been about subways, as in my current city this is a big transit player, this time around for me also..
And so we can learn things from each other which is nice...

But yes in your dense cities, as your final image shows.. if you have reached the traffic limit ( of any network type really).. I would also place a high priority on this as also besides the large congestion you want to know what the traffic figures are as they are reported accurately..

One reason i stopped using so many connections to other cities is because its to difficult for me to keep traffic under control.
Thats why it is so impressive to me ... your ability to manage all this traffic in these situations..

But , yes another fine update by you !!

[pierreh]

In continuation to my previous post, here is the solution I implemented in Arcens, to deal with the saturated subway and GLR links. Relatively to the last picture of that post, the surface view shows the added subway-to-GLR transition, and the resulting reduction of usage on the GLR tracks going to the railway station:



The corresponding view at the subway level shows how this new transition is connected to the existing subway tunnel. That tunnel no longer shows the saturation figure, this is more in line with what is measured at the other end of the link in Cherenne;



The situation will be further monitored, but for now I consider that this case has been dealt with, at least for a while, and I'll turn my attention to other traffic issues in the cluster.

[brian51]

Pierre.

this worked out very nicely for you !
As you well know and  I have mentioned before in these types of CJ updates.., traffic improvements do not always work out n the ways
we had planned or hoped for.. i think  because traffic situations i sc -4 can be quite complex..!!

But very nicely done update here, that clearly shows the original traffic congestion issues, the plan you implemented to fix the situation,
and than finally the sought after results of that fix,,,

Keep these great Cj updates coming my friend !!

[Guardian]

If those stations both experience increased usage, does that not create more of a bottleneck for the main line though?

Interesting to see the work-around fit in so close to the primary site and it not affect congestion.

[pierreh]

Thanks Brian and Guardian for your comments!

@Guardian: before answering your interesting question I need to understand properly what you mean by "those stations both (...)" - are you referring to the two 'subway squares' that end the subway tunnels on the lower left quarter of the last picture in my previous post?

[Guardian]

@Guardian: before answering your interesting question I need to understand properly what you mean by "those stations both (...)" - are you referring to the two 'subway squares' that end the subway tunnels on the lower left quarter of the last picture in my previous post?

Those would be the ones. I guess they're more transitions than anything? 

[pierreh]

Yes indeed, they are transitions, between the subway on one side and the GLR on the other side. The subway square, which is placed on the center tile of the transition, is where the subway tunnel is connected on the subway side.
In that sense, these transitions switch subway traffic to GLR traffic, and vice-versa, without any loss or gain. They do not constitute any bottleneck, their limitation is that of the subway tunnels, which can carry a maximum of 65535 subway users.
So they are not 'stations'; a typical subway station has one or more staircases, that represent the ability to switch between pedestrian traffic and subway traffic. RTMT also includes more complex stations such as, for example, combined subway+bus stations, where there is also switching between bus traffic and subway traffic, etc.

[Guardian]

Ah, makes sense now. Thanks for the clarification!

I really misunderstood that at first. My bottleneck comments make no sense now.

[pierreh]

I have been quite inactive lately, because of some family-related issues, which will continue to keep me busy until the end of February.

Still, I have found a few opportunities to play the game, and for a diversion to the Talaran 9-cities cluster, I have returned to an older 6-cities cluster. That cluster was called 'Sambey', since that was the name chosen for the entire region. Actually the Talaran cluster is also in that region. Because of this, and also as I don't want to start yet another CJ, I'll document here what I have started doing on the 6-cities Sambey cluster.

In the Sambey cluster I wanted to see the interaction between 'specialized' cities. About at the time when I stopped playing with that cluster, in late 2014 (!), it looked like this:



The cluster was composed of:
- 4 residential cities: Deliambert, Treymont, Aveillans and Jonolray
- 1 commercial city: Lessy
- 1 industrial city: Parnal

Because Sims in the residential cities had to go 'elsewhere' to find jobs, this entailed inter-city flows, which are shown in the next picture:

Quite soon those flows became difficult to manage: highways, railways and subways linking the cities reached saturation, were doubled, trebled, with little effect. As it was not possible to overcome the game's limitations, I left the cluster aside, and went on to develop Talaran with 'normal' cities (and yet considerable inter-city flows, as documented earlier in this CJ).

Lately I have returned to that old Arcens cluster. What I am doing is to 'normalize' its cities, by adding commercial zones to the 4 residential cities, and residential zones in the commercial city of Lessy. For the time being I am not doing anything with the industrial city of Parnal. I am also reviewing the highway interchanges and access ramps, taking advantage of some of the RHW features. This seems to be going fairly well.

I'll be documenting (slowly) the progress of that effort, in parallel with the further development of the Talaran cluster.

[brian51]

Pierre,

This was an interesting post for me..

Because I played regionally in sc4 in a  similar fashion . Using specialized "job" cities .. for the most part..like you have..
Although I would often later include at least some kinda small residential populations even in these "job " cities..

Most of the job were "filled" by Sims who commuted from other cities,,

Part of the reason , that I like to do this was to than be able to make the near by residential cities a larger population for the lands I had to build upon.

Also o sometimes like to go back and work on "older" cities i have not worked on for quite some time

And yes, thanks..
I did wonder if this was all from the "same" region.
But I have a request for you :

I was wondering if in your next posting, you could give us a new update on what our current region population is currently ?

[pierreh]

Thanks for your interesting comments, Brian.

Population statistics are easy to produce, because I keep a small Excel table about them. Here it is, with the tallies for the Sambey and Talaran clusters, and the total for the region:



Currently the largest city, in terms of population, is Prandergal with 1'188'115 Sims.

It is interesting that you mention that you have been playing with 'specialized cities'. I don't know whether you remember my postings about the Sambey cluster, at the time my CJ was hosted on Simmania. I encountered tremedous saturation problems with the inter-city traffic. Actually those problems are still present. I'll be documenting a few of them in later posts. Did you ever experience serious saturation problems with the inter-city traffic in your specialized cities?

[brian51]

Did you ever experience serious saturation problems with the inter-city traffic in your specialized cities?

Yes,

and I think that was part of the reason i gravitated away from regional play, really..

But i will be looking forward to your future postings on 

your Sambey cluster

[pierreh]

I have resumed working on the 6 cities in the older 'Sambey' cluster. As part of that work I am changing the old parclo highway junctions by more modern junctions using RHW. This has some negative side effects that I can document here in one case. Here is a part of the commercial area of Lessy, with the reworked junction on the top right of the picture:



The effect of the rework is better seen in the zone view of the same area:



A few roadways and a railway are cut, because essentially of a MIS ramp that precludes crossing the highway by either an overpass or an underpass:
1 - a road is cut; the left portion of the road has already been converted to a street;
2 - a railway is cut; this quite inconvenient because there is no way to reroute this portion of railway tracks;
3 - an avenue is cut;
4 - this used to be an entrance/exit link between the highway and the city roadways, there is no longer enough room for that link to be preserved there.

Once the area is reworked I'll show the new configuration in a future post.