Railway crossing/split/Intersection

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Railway crossing/split/Intersection

Post by Tanafen » Wed Jul 11, 2018 1:51 pm

Hello. I am constructing a massive megabase, with more than 100 trains, and I am having some problems with them stopping a wrong intersections. All the trains are 3-10-3, so they are quite large and go two ways.

My current problem is this right way split

Image

It worked, sorta, but the trains kept stopping even though the rails were clear far ahead, though much further down the path there was a crossing, but that crossing had signals as well.

So I tried looking around the internet for some helt, and I found this that I blueprinted, but with this, the trains wont run at all.

Image

What am I doing wrong, and what would you recommend for such large trains?

Zavian
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Re: Railway crossing/split/Intersection

Post by Zavian » Wed Jul 11, 2018 2:20 pm

I suggest this tutorial on how to signal raIl line. https://www.reddit.com/r/factorio/comme ... ts_23_and/

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Re: Railway crossing/split/Intersection

Post by Loewchen » Wed Jul 11, 2018 2:20 pm

Tanafen wrote:What am I doing wrong, and what would you recommend for such large trains?
All signals into an occupied block are closed, if the block is big as it is in the lower right of the second screenshot, then the gap which other trains can not enter is big, so keep the size of blocks as small as practically possible.
Chain signals only have the purpose to prevent a train from entering an unoccupied block if it can not clear it, so it does not hinder another train from crossing the block if they could. If you place chain signals non nonsensical you will destroy throughput in you network. Only place chain signals if you know why, if you don't know how they work at all, look it up. The ingame train tutorial explains all of this, try it out.

Tanafen
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Re: Railway crossing/split/Intersection

Post by Tanafen » Wed Jul 11, 2018 2:30 pm

I dont think I understand. You have to use chain signals when using two-way trains right?

So whenever the rails cross, you HAVE to have a signal dont you? Otherwise the trains would crash.

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Re: Railway crossing/split/Intersection

Post by Zavian » Wed Jul 11, 2018 2:43 pm

Whilst we can help you fix this junction, what you really need is to learn how to signal rail lines and junctions properly. Which is why I suggested that rail signal tutorial. All this is explained in that tutorial.

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Re: Railway crossing/split/Intersection

Post by Loewchen » Wed Jul 11, 2018 2:44 pm

Tanafen wrote:I dont think I understand. You have to use chain signals when using two-way trains right?

So whenever the rails cross, you HAVE to have a signal dont you? Otherwise the trains would crash.
Having two-way track with more than one track makes no sense, you would increase throughput just by having one track per direction. But you already abandoned the two-way idea in the second picture already anyway?!
Go with the tutorials, without knowing the basics discussing some niche setup is not going to help you.

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Re: Railway crossing/split/Intersection

Post by Tanafen » Wed Jul 11, 2018 3:53 pm

Okay, I read the entire tutorial, and watched a few on youtube, and then tried myself.

Now, I have a rather congested intersection as you can see below.
Image

and zoomed in.
Image

is this correct?

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Re: Railway crossing/split/Intersection

Post by Loewchen » Wed Jul 11, 2018 4:25 pm

Tanafen wrote:is this correct?
No, if you actually intent to have two way tracks, then you have to signal it, so you can only have one train on a single track at the same time, otherwise two with different direction will keep each other from progressing completely. Why are you trying to use two way tracks?

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Re: Railway crossing/split/Intersection

Post by Tanafen » Wed Jul 11, 2018 5:01 pm

maybe I miscommunicated. I dont want more than one train on each track. I just want the same train to go both ways. So in the picture I have 7 trains going from east to west and back again, to their individual stations. Then I have 10 trains going north and south and back again, also to their individual stations.

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Re: Railway crossing/split/Intersection

Post by Loewchen » Wed Jul 11, 2018 6:48 pm

Tanafen wrote:I dont want more than one train on each track.

Place signals before and after every crossing of tracks, if you care to prevent blocking make sure to have at least a gap of one train length after each intersection and use non chain signals only on intersection exits.

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Re: Railway crossing/split/Intersection

Post by nuhll » Wed Jul 11, 2018 7:59 pm

Its so easy.

BEFORE every junction you place a chain signal (and after each crossing) at the end you place a normal signal.

YOU NEED to have space BEFORE the chain signal for the biggest train you have. And you MUST have atleast enaught space for your biggest train AFTER.

Then you place normal signs (again, it depends how big your trains are) until the next junction.

Its so easy.

What you did is 110% wrong because trains will cause dead locks (you need to manual free the trains).

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Re: Railway crossing/split/Intersection

Post by Tanafen » Wed Jul 11, 2018 8:31 pm

I appreciate the help, but I disagree. It most definitely is NOT easy. Two tracks, sure, but 17 as I'm doing? Really complicated. What is even more annoying is that I have found 0 tutorials or demonstrations about anything resembling this. All examples are with 2 trains crossing, and not with a whole bunch.

The terminaology is also confusing.
Crossings, junctions, intersections, sections, blocks, what is the difference between them all?

Is is possible at all to do a compressed crossing like the one in my images at all, do I need to remove all the signals in the middle of all the tracks? Replace them? So do I need to remove this entire layout to make an enormous crossing for such big trains?

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Re: Railway crossing/split/Intersection

Post by Tanafen » Wed Jul 11, 2018 9:05 pm

I know I'm a bit dense on this, but I would really like for someone to spell it out for me...with more than words please.

All over the forums I see beautiful and creative crossings for multiple trains to cross in all kinds of directions, so the same trains can go both east, west, north and south. I'm not looking for that.
I see many examples of 2x2 intersections where each track only goes one way. I'm not looking for that either.
All examples I've seen are with one train car with 1-2 wagons behind it. I'm not looking for that either.

Image

Lets take this example. Here I want 3 trains (3-10-3) each going north AND south on its own track. And 3 trains (3-10-3) going east AND west.

a) is it possible to make this work reliably or are the tracks too tightly packed? (How far apart do they need to be)
b) Whick signals shall I use and where? What distance do they need to be placed?

Please, I really need to figure this out.

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Re: Railway crossing/split/Intersection

Post by DaveMcW » Wed Jul 11, 2018 9:26 pm

This is inefficient but foolproof:

1. Do not put any signal inside the intersection.
2. Put paired chain signals at every entrance/exit.
3. Put paired rail signals one train length away from the intersection in every direction.

Once you know what you are doing, you can combine steps two and three by using the correct chain signal + rail signal pair on entrances/exits. You can also put some paired chain signals inside the intersection.

(Once you REALLY know what you are doing, you will stop using 2-way track.)

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Re: Railway crossing/split/Intersection

Post by nuhll » Wed Jul 11, 2018 9:55 pm

I did the MINIMUM on signals, better is to put chain signals between ENTRY and EXIT (or the other way around, if possible) because then trains can move faster bc the blocks gets faster emptied (trains occupie blocks)

But since you have such weird junctions, i guess, it doesnt matter.

And yes, its 100% easy, just read what iw rote, do it, thats all oyu need to know. My english is not perfect, so if you dont understand my sentences i can try to explain it.

As i startet it was also WAY hard for me.

Other signals might work, but it might happen that your trains get stuck, and thats the highest prioritiy to not happen. If you follow me "guide", it cant dead lock.

But notice, the side of the signals DEPENDS ON YOUR WAY THE TRAINS TRAVELS (but i guess u know that, just put other side of track, if you need other way)


Minimum signals:
1. at every start of a junction put a chain signal
2. at every end of a junction put a normal signal
3. enaught space before and after each junction to fit the biggest train you have

better:
Put as many chain signals "as possible" (it cant hurt) between the different sections of the junction
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Re: Railway crossing/split/Intersection

Post by Jap2.0 » Wed Jul 11, 2018 10:00 pm

You'll want this:
img.png
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Re: Railway crossing/split/Intersection

Post by Tanafen » Wed Jul 11, 2018 10:09 pm

THANK YOU! At long last. Thanks everybody. I think I got it now.

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Re: Railway crossing/split/Intersection

Post by PacifyerGrey » Fri Jul 13, 2018 3:03 pm

While Jap’s example follows general guideline and will mostly work I do not suggest it in your case.
Take it and remove all signals inside the intersection leaving only perimeter ones and it will never deadlock as opposed to the picture

I would strongly suggest you drop the idea of dedicated 2-way tracks for all trains. This takes too much space and will cause many accidental difficulties all over the place. It is much more efficient to have single way tracks all around as well as smaller trains. This allows for much more flexibility, less deadlocks and more throughput. This might sound weird to you but 3-10-3 trains are only effective when most of their path is uninterrupted by intersections. If you start using many of those you will get progressively more complex and deadlocking system as long trains cause even more obstacles for other trains. X cross intersections are the worst on this part and something like 7x7 X intersection like you showed on your screenshot will deadlock like mad or you have to signal it like I said above for even less throughput

So I do encourage you consider more universal one way pair of tracks or a 4 track design if you lack 2 track system throughput

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Re: Railway crossing/split/Intersection

Post by Jap2.0 » Fri Jul 13, 2018 5:54 pm

PacifyerGrey wrote:While Jap’s example follows general guideline and will mostly work I do not suggest it in your case.
Take it and remove all signals inside the intersection leaving only perimeter ones and it will never deadlock as opposed to the picture

I would strongly suggest you drop the idea of dedicated 2-way tracks for all trains. This takes too much space and will cause many accidental difficulties all over the place. It is much more efficient to have single way tracks all around as well as smaller trains. This allows for much more flexibility, less deadlocks and more throughput. This might sound weird to you but 3-10-3 trains are only effective when most of their path is uninterrupted by intersections. If you start using many of those you will get progressively more complex and deadlocking system as long trains cause even more obstacles for other trains. X cross intersections are the worst on this part and something like 7x7 X intersection like you showed on your screenshot will deadlock like mad or you have to signal it like I said above for even less throughput

So I do encourage you consider more universal one way pair of tracks or a 4 track design if you lack 2 track system throughput
Yes, a standard rail layout is much better. Where would my design deadlock, though? There are only chain signals inside the intersection, so no trains would ever stop inside the intersection (assuming there was a large enough exit block) - removing all the signals inside the intersection would do the same thing, only it would not allow more than one train inside the intersection at once.
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Re: Railway crossing/split/Intersection

Post by PacifyerGrey » Sun Jul 15, 2018 11:49 am

Jap2.0 wrote: So I do encourage you consider more universal one way pair of t
Yes, a standard rail layout is much better. Where would my design deadlock, though? There are only chain signals inside the intersection, so no trains would ever stop inside the intersection (assuming there was a large enough exit block) - removing all the signals inside the intersection would do the same thing, only it would not allow more than one train inside the intersection at once.
Your design will deadlock with trains entering the intersection simultaneously in a spiral manner. While probability is low it can easily happen as such network has a lot of other intersections which might still help deadlocking it

Keeping the intersection as a single block will remove this possibility while reducing throughput

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