3 and 4 way intersections

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Re: 3 and 4 way intersections

Post by SaiMoen »

Had this interesting 4-way junction where there is a small bidirectional part. Got the following results from testing it once: 1: 53, 2: 39, 3: 47, s: 46. I call it the Celtic Nope, but I don't even know if this is similar enough to the Celtic Knot.


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Re: 3 and 4 way intersections

Post by hansjoachim »

aaargha wrote:
Mon Nov 22, 2021 8:45 pm
Good stuff guys! It's really heartening to see this carried on!

There is so much spirit of invention in this community that I have no doubt this this thread will generate a lot of discussions/innovation, even my old thread had a lot of activity long after I dropped off (thank you to everyone who participated, especially all of you that has shared designs and insight to keep it going - you guys are all amazing!) Keep collaborating, innovating and having fun - I have no doubt this is in good hands.

My request: go all the way! Make this the definitive repository for intersection testing. Make my thread obsolete for anything but history/archaeology. (Surpass Metal Gear etc. etc.) Most (if not all) of the blueprints from the old thread can still be accessed using the Wayback machine or, if you're interested, I probably have all my source material, blueprints included, on some drive somewhere, let me know if you guys want it and I'll have a look this weekend.

And, as a parting "gift" I shall submit my magnum opus for evaluation: one of the greatest works of engineering of today - right up there with the Apollo Program, the Large Hadron Collider, sliced bread, or double ply toilet paper (in case anyone was unsure whether this part is a shitpost or not ;) ).

Finally, good luck, have fun, and Godspeed!
Thanks aaargha! You have been missed

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Re: 3 and 4 way intersections

Post by Hovedgade »

I have made a some blueprints myself and tested them on the testbench. Feel free to add them to the list. Altough I beleive the the stack interchange is a little too similar to the Cross by Tallinu, so adding that one may not be preferential.

Small turbo roundabout
Set 1; 78, set 2: 61, set 3: 43 ⇒ Score: 61


Compressed turbo roundabout
Set 1: 91, Set 2: 71, Set 3: 42 ⇒ Score: 68


Stack interchange
Set 1: 73, Set 2: 50, Set 3: 48 ⇒ Score: 57


Additionally I also tested a intersection by u/Communist_Fella with the following results:
Set 1: 105, Set 2: 77, Set 3: 48 ⇒ Score: 77

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Re: 3 and 4 way intersections

Post by Kano96 »

Lubricus wrote:
Mon Nov 22, 2021 10:14 am
Checking the other intersections. It's only a slightly tighter version of this https://factoriobin.com/post/01B6XBlB
So it's an improvment but slight.
True, I replaced it with your new version.
Lubricus wrote:
Mon Nov 22, 2021 12:37 pm
It's hard to find the separete scores for the LHD and RHD versions. For me the LHD and RHD versions is separate designs and shoundn't be lumped together. Is it possible to filter by LHD and RHD? Maybe also spacing between the rails. I chose LHD/RHD and spacing after the intersections I design not the other way around so for me it would be best to have a straight list with all the designs.
Yeah I agree, LHD and RHD are technically different designs, the current organization is a compromise. We could just add a new category for RHD/LHD and put them in two separate lists, but as you said, if you want to actually compare the different designs it's easier to have one big list containing all designs. We are just trying to find a middle ground between the two. Also the old crushed wide had two different rail spacings for RHD/LHD which is something we don't allow, so those two should have been two different entries.

Filtering the list is currently impossible. I would love to make this possible and then just have one big list for all designs, but I did not find a way to do it in a forum post.

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Re: 3 and 4 way intersections

Post by Kano96 »

FWD wrote:
Mon Nov 22, 2021 11:04 am
Thank you for making this, the tester works wonders and is easy to use as of 4.2.1.

4 ways, 2 lanes, 2-4 trains, LHD, single buffered intersection. I believe the design might exist under the name "Turbine" even though I happened to make it naturally, but I didn't see it online yet. I use a smaller 2-3 trains version on my main.

Compact and easy to resize, and looks quite good.

LHD scores : 39/25/24

Image

https://imgur.com/a/XK07MO0

Pretty cool, it does look quite nice, but tbh that score isn't very good. Right now you separate your straight and right turn path in front of the junction, just to then let them intersect again once they enter the center. You can easily avoid this by just switching the two paths, so have the right turn closer to the center and the straight on the outside, which should significantly increase performance. That would probably also give you some space in the center to separate the paths with chain signals, which is the second big problem holding it back.

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Re: 3 and 4 way intersections

Post by Kano96 »

mmmPI wrote:
Mon Nov 22, 2021 12:43 pm
Lubricus wrote:
Mon Nov 22, 2021 10:14 am
Checking the other intersections. It's only a slightly tighter version of this https://factoriobin.com/post/01B6XBlB
So it's an improvment but slight.
This is correct !

i think there was a misunderstanding, i wanted to say that your version, the more compact, is missing 4 chain signal on the website factoriobin, i saw that from the screenshot because when looking at the blueprint i didn't notice.

I think it should replace the existing (obsolete because bigger) Crushed Wide (LHD) eventually but tests takes time :).

[I did the conversion from RHD to LHD so i'm responsible for the suboptimal existing version that's why i recognized it, i tried to make it as similar as the RHD and as small as possible, i think you came up with a better junction from scratch since small size was the goal ;I would tend to agree LHD and RHD version sometimes feel like a different design, which could yield different score]



I tried to make a small junction of my own and it ended up being a more compact RHD version of "compact". in the 4 way 2 lane unbuffered (44x44 RHD instead of 46x46 RHD). where the LHD version is only 36x36 !
Compact RHD 44x44


In another attempt to make it smaller I ended up with a symetrical version of the " asymetric 6 tile RHD" although larger, 34x34 instead of 30x29.
symetrical cross 6 tile
True, replaced the rhd compact with yours.

Yeah I wanted to add that symmetrical cross already, it's a pretty natural design. I changed the signaling to be optimal for testing and made an LHD version. It scored a Set1:51, Set2:40, Set3:50, Score:47 which puts it at the top of unbuffered 2lanes.

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Re: 3 and 4 way intersections

Post by farcast »

Kano96 wrote:
Wed Nov 24, 2021 5:27 am
Filtering the list is currently impossible. I would love to make this possible and then just have one big list for all designs, but I did not find a way to do it in a forum post.
Put each entry into a new reply, then we can use the forum search. :D
Efficient inefficient design.

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Re: 3 and 4 way intersections

Post by SaiMoen »

Testbench v4.2.1, Factorio v1.1.46
3-Way, 2-Lane, Unbuffered, spacing is 4 everywhere. Currently better than the only thing listed on that section.
R452736.png
R452736.png (740.96 KiB) Viewed 7150 times

Results with exit blocks; 1:45, 2:27, s:36.

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Re: 3 and 4 way intersections

Post by farcast »

Clockwork
Clockwork in action.gif
Clockwork in action.gif (404.6 KiB) Viewed 7116 times
What could be better than having synchronized crossings? Having synchronized straights too!

RHD & LHD Score: 81
Set 1: 83
Set 2: 80
Set 3: 82

Given scores were obtained with 30 rail tile signal spacing for incoming trains only. It's okay to add this to the list.

Signal spacing seems to be less important now, of the spacings I've tested (4, 14, 19, 27, 30 rails) sets 1 & 3 were always above 80, and set 3 was always stable. The worst I've seen was 70 TPM for set 2, and that was with 4 rail spacing.

An earlier version of clockwork just wouldn't re-synchronize after a disruption with 27 rail signal spacing and needed 30, but rail spacing isn't much of an issue now. The only relevant difference from then is that the buffers were lengthened from 27 rails to 30 rails. Maybe increasing the buffer size increased the tolerance? Maybe there's a sweet spot for buffer size where signal spacing isn't needed anymore?

My current theory is that crossings have a sort-of resonant frequency from when a chain signal turns yellow to when that same chain signal turns yellow again. Signal spacing helps with synchronization by throttling train arrivals to a frequency similar to that of the slowest crossing. Buffer size should only matter so far as it affects how much trains need to slow down and how far away the next crossing is, and as a consequence, how quickly they clear the previous crossing and the next crossing.

An intersection can be synchronous if the graph of the buffers is 2 colorable, where 2 buffers share an edge if they are consecutive in the direction of travel, or if the paths cross at the end of both buffers. More intuitively, you should be able to mark each buffer as either "train" or "no train", alternating as you trace each path until you've marked every buffer without 2 "train"s or "no train"s in a row and without 2 "train"s both pointed at or away from where they would immediately cross.

Benefits of designing intersections this way:
-consistent mid-high tier throughput in all situations
-potentially linear throughput scaling with more lanes since synchronous crossings in series won't lower throughput
-very fun to watch

Downsides:
-Extremely finicky
-restricted max throughput
-synchronized trains means synchronized re-paths

Efficient inefficient design.

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Re: 3 and 4 way intersections

Post by Kano96 »

farcast wrote:
Wed Nov 24, 2021 7:35 am
Kano96 wrote:
Wed Nov 24, 2021 5:27 am
Filtering the list is currently impossible. I would love to make this possible and then just have one big list for all designs, but I did not find a way to do it in a forum post.
Put each entry into a new reply, then we can use the forum search. :D
Simple, yet elegant. I'll make sure to remember this for the next intersection post. :P
SaiMoen wrote:
Thu Nov 25, 2021 4:58 pm
Testbench v4.2.1, Factorio v1.1.46
3-Way, 2-Lane, Unbuffered, spacing is 4 everywhere. Currently better than the only thing listed on that section.
R452736.png

Results with exit blocks; 1:45, 2:27, s:36.
Your design is essentially equivalent to the existing entry, so it didn't make any sense that you scored that much higher. I restested the original design and it also scored a 46|27 , meaning the original results were somehow messed up. Thanks for the contribution, I added a 4tile version to the entries blueprints.

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Re: 3 and 4 way intersections

Post by Kano96 »

aaargha wrote:
Mon Nov 22, 2021 8:45 pm
Good stuff guys! It's really heartening to see this carried on!

There is so much spirit of invention in this community that I have no doubt this this thread will generate a lot of discussions/innovation, even my old thread had a lot of activity long after I dropped off (thank you to everyone who participated, especially all of you that has shared designs and insight to keep it going - you guys are all amazing!) Keep collaborating, innovating and having fun - I have no doubt this is in good hands.

My request: go all the way! Make this the definitive repository for intersection testing. Make my thread obsolete for anything but history/archaeology. (Surpass Metal Gear etc. etc.) Most (if not all) of the blueprints from the old thread can still be accessed using the Wayback machine or, if you're interested, I probably have all my source material, blueprints included, on some drive somewhere, let me know if you guys want it and I'll have a look this weekend.

And, as a parting "gift" I shall submit my magnum opus for evaluation: one of the greatest works of engineering of today - right up there with the Apollo Program, the Large Hadron Collider, sliced bread, or double ply toilet paper (in case anyone was unsure whether this part is a shitpost or not ;) ).
No Gods


Finally, good luck, have fun, and Godspeed!
Thanks for laying the foundation to make all of this possible. :)

Also we don't accept entire train networks as submissions, sorry. :P

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Re: 3 and 4 way intersections

Post by Kano96 »

causa-sui wrote:
Mon Nov 22, 2021 3:32 pm
Factoriointersection wrote:
Sun Nov 21, 2021 9:41 pm
Do you have the LHD version as well? I'll test and add this one
I asked Bocian to convert it to LHD and he did, because he's a swell guy

That design is already submitted under the name "Whirlpool" in the 2lane buffered category. I added the LHD version.

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Re: 3 and 4 way intersections

Post by Kano96 »

SaiMoen wrote:
Mon Nov 22, 2021 10:24 pm
Had this interesting 4-way junction where there is a small bidirectional part. Got the following results from testing it once: 1: 53, 2: 39, 3: 47, s: 46. I call it the Celtic Nope, but I don't even know if this is similar enough to the Celtic Knot.

You need to have safe exit blocks when testing an intersection, look at the "Testing" section of the post for an explanation (I added it recently, probably after you commented, so not your fault). I retested it with safe exit blocks and got a 48|37|46|44 . The signaling was already optimal and I like the aesthetics, so it's added to the post. Also the name lol :D

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Re: 3 and 4 way intersections

Post by SaiMoen »

Kano96 wrote:
Fri Nov 26, 2021 12:59 pm
SaiMoen wrote:
Mon Nov 22, 2021 10:24 pm
Had this interesting 4-way junction where there is a small bidirectional part. Got the following results from testing it once: 1: 53, 2: 39, 3: 47, s: 46. I call it the Celtic Nope, but I don't even know if this is similar enough to the Celtic Knot.

You need to have safe exit blocks when testing an intersection, look at the "Testing" section of the post for an explanation (I added it recently, probably after you commented, so not your fault). I retested it with safe exit blocks and got a 48|37|46|44 . The signaling was already optimal and I like the aesthetics, so it's added to the post. Also the name lol :D
Yep I can't read :cry:
Oh and also, the size is listed incorrectly because I forgot to remove the big electric poles so the intersection itself is actually 48x48, not 61x61.

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Re: 3 and 4 way intersections

Post by SaiMoen »

Considering the original post asks to notify about errors in this thread I've looked through it to help out:

- The score calculation divides by (2/lanes), while I assume it should multiply instead:
Example: on the 4-way 4-lane unbuffered section, the top junction (Christmas) combined set term (set1+set2+set3) is 230, then we end up with (76.66...)/(2/4) = 153.33... whereas the listed score is 38 so the calculation should probably be score = ((set1+set2+set3)/3) * (2/lanes)

- Irregular power pole usage:
Sometimes the blueprint includes power poles or unnecessary rails at the edge, which could cause the listed size to be larger than what this thread should consider the 'intersection' to be. For instance I forgot to take out that stuff before sending the blueprint of my Celtic Nope so now the listed size of 61x61 is larger than the intersection part which is 48x48. Now in this case it was my fault that I forgot to take out that stuff in the first place, but maybe there could be a reminder for people to take out the power poles (with maybe an except for the one in the middle) and straight rails at the edge/ends.

- Miscellaneous small mistakes:

Will trust the buffered/others parts and only look at the unbuffered ones since I don't feel like counting pixel to get some exact size :D .

4-way
2-lane

4. Asymetric 6 tiles
Asymmetric is spelled with 2 m's.
The size is listed as 30x29, but it looks like 30x30 on the blueprint. Not sure if I'm missing something.

8. Celtic Nope
Already mentioned the size discrepancy.

9. Wide B
The chain signals at the starts/ends seem a bit unnecessary.

10. Weird Intersection
Listed as 43x44 while appearing to be 44x44.

11. Foundation
Has power poles, size appears to be 46x46 instead of the listed 49x49, unless it is asymmetrical? Can't quite see it.

4-lane

4. 4lane CelticKnot
Listed as 71x71 while appearing as 72x72.

3-way
2-lane

1. Simple 3-way
Listed with spacing 4 but has spacing 6.

4-lane

1. Simple 3-way 4-lanes
Includes exit blocks, real size is 62x44, spacing is 6 not 4.

I highly appreciate this thread and the effort that goes into this, so I hope this helps to maintain it. :)

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Re: 3 and 4 way intersections

Post by Kano96 »

SaiMoen wrote:
Sat Nov 27, 2021 4:18 pm
Considering the original post asks to notify about errors in this thread I've looked through it to help out...
Yep, score = ((set1+set2+set3)/3) * (2/lanes) is the correct formula and it now also says so in the description.

- Irregular power pole usage:
We don't really have strict rules for included powerpoles or extra rails, maybe it would make sense to define some. Sometimes I adjust blueprints to make them uniform, it depends on my mood atm. There are also some instances where it's a tricky decision, like when it comes to my foundation 2lane unbuffered, which does include powerpoles and extra rails, but this is because it's a design taken from an entire rail blueprint set. When you want to use the entire set, the intersection will look exactly as it's shown in the post. Now that I think this through tho, it would probably make more sense to have one uniform standard, even if the linked blueprint contains a slightly different version.

Another related issue is also the question of rail signal placement. You can place signals in multiple different ways, like purely performance optimized or allowing trains to repath while waiting or like they would be in an actual rail set. All of these make some sense from a gameplay perspective but deliver different test results. Until now, we just let the author decide how to signal them for the most part, but we'll probably have to enforce one of the methods to keep test results comparable.

As for the celtic nope, I noticed the size problem while adding it to the post already. This is why I edited the blueprint to it's minimum size and removed the powerpoles, but then promptly forgot to edit the size in the spreadsheet :S . It's fixed now.

Thanks for finding all these issues, greatly appreciated :D . Most of them should be fixed, the signaling of wide B will be adressed once we decide on which way to go with it, the chains at the exit definitely make no sense. As for 4lane 3-way, I have to discuss this with HansJoachimAa first.

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Re: 3 and 4 way intersections

Post by mmmPI »

farcast wrote:
Fri Nov 26, 2021 7:33 am
What could be better than having synchronized crossings? Having synchronized straights too!
I find it hard to believe that a junction making straight tracks cross could yield a good score. And it took me time to realise that there was this unecessary crossing added.
It looks even better than the first one, it really is an efficient inefficient design congrats !

And thanks for explaining. It may be of some use for an attempt at no-signal networks, based on sychronized train :)

Kano96 wrote:
Wed Nov 24, 2021 6:30 am
Yeah I wanted to add that symmetrical cross already, it's a pretty natural design. I changed the signaling to be optimal for testing and made an LHD version. It scored a Set1:51, Set2:40, Set3:50, Score:47 which puts it at the top of unbuffered 2lanes.
I'm not sure i should have credits on this one, since it's a pretty natural design ;) , but i couldn't find it in the googledoc. ( there is the 4 lane version called christmas ).

There is this other junction that was made after Koub made a thread about rail spacing. The goal was to make a 32x32 junction for it to be chunk-aligned. This is not my creation but it was the result that was choosen.(i think it was from hansjoachim)The rail spacing is 6 tile too, there was unsuccessful attempt to make it smaller by me. :). I didn't found it in the googledoc, it look like the "compact spiral" in the 2 lane unbuffered junctions from the csv/previous thread but with improved signaling it should score much better.
ChunkalignedSpiral







The following one is a RHD version of "No God" just in case


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Re: 3 and 4 way intersections

Post by Lubricus »

Kano96 wrote:
Sat Nov 27, 2021 8:54 pm
SaiMoen wrote:
Sat Nov 27, 2021 4:18 pm
Considering the original post asks to notify about errors in this thread I've looked through it to help out...
Yep, score = ((set1+set2+set3)/3) * (2/lanes) is the correct formula and it now also says so in the description.

- Irregular power pole usage:
We don't really have strict rules for included powerpoles or extra rails, maybe it would make sense to define some. Sometimes I adjust blueprints to make them uniform, it depends on my mood atm. There are also some instances where it's a tricky decision, like when it comes to my foundation 2lane unbuffered, which does include powerpoles and extra rails, but this is because it's a design taken from an entire rail blueprint set. When you want to use the entire set, the intersection will look exactly as it's shown in the post. Now that I think this through tho, it would probably make more sense to have one uniform standard, even if the linked blueprint contains a slightly different version.

Another related issue is also the question of rail signal placement. You can place signals in multiple different ways, like purely performance optimized or allowing trains to repath while waiting or like they would be in an actual rail set. All of these make some sense from a gameplay perspective but deliver different test results. Until now, we just let the author decide how to signal them for the most part, but we'll probably have to enforce one of the methods to keep test results comparable.

As for the celtic nope, I noticed the size problem while adding it to the post already. This is why I edited the blueprint to it's minimum size and removed the powerpoles, but then promptly forgot to edit the size in the spreadsheet :S . It's fixed now.

Thanks for finding all these issues, greatly appreciated :D . Most of them should be fixed, the signaling of wide B will be adressed once we decide on which way to go with it, the chains at the exit definitely make no sense. As for 4lane 3-way, I have to discuss this with HansJoachimAa first.
I don't think that having the "extra" chainsignals in front of the intersections for repathing is needed any longer when we have Station limits so the trains don't repath between different stations. I would wote for signaling for pure performance.

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Re: 3 and 4 way intersections

Post by farcast »

mmmPI wrote:
Sat Nov 27, 2021 9:47 pm
farcast wrote:
Fri Nov 26, 2021 7:33 am
What could be better than having synchronized crossings? Having synchronized straights too!
I find it hard to believe that a junction making straight tracks cross could yield a good score. And it took me time to realise that there was this unecessary crossing added.
It looks even better than the first one, it really is an efficient inefficient design congrats !

And thanks for explaining. It may be of some use for an attempt at no-signal networks, based on sychronized train :)
Thanks, I'm glad you like it! The extra crossing is actually very necessary. It makes lefts go through 3 crossings while straights go through 4, causing lefts and straights to exit off-beat of each other, so one never needs to stop to let the other pass.

For a no-signal network, just remember that the entire network will need to be 2 colorable, otherwise the different intersections could be out of sync with each other.
Efficient inefficient design.

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Re: 3 and 4 way intersections

Post by mmmPI »

Yes necessary for your junction to function ! Not necessary like left turn for RHD driver where you NEED to cut the path of the person going straight from the opposite direction.
Usually straight tracks are well straights :) more like the right turn for rhd driver, where you do not need to cut any path you just merge.

And the "better scoring" junction usually makes it so that 2 left and 2 right turns can be done from driver coming from opposite direction at the same time without crossing path for the very reason of trying to not have one stop to let the other pass, which can be also be achieved by some geometric magic it seems :)
farcast wrote:
Sat Nov 27, 2021 11:28 pm
For a no-signal network, just remember that the entire network will need to be 2 colorable, otherwise the different intersections could be out of sync with each other.
this left me thinking but it's a bit off topic so i won't develop here but i'm hoping that it can be made less strict than having the whole network strictly 2 colorable to make it easier to expand using buffer area with variating waiting time to allow for resync at the exit when needed for a junction. So many things to try :D

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