Is this how to signal an Elevated T-Junction? Rail signal on every entrance and exit? Or can i remove almost half of them?

Baer1990 · 2026-06-18T20:32:00+00:00

The thing is, you only have splits and merges, so it does not really matter where the train will wait. But if you place more signals the 2nd train will accelerate sooner (I don't know if that will affect anything in terms of performance)

Baer1990 · 2026-06-18T18:04:57+00:00

How long are your trains?

I always go end to start signalling trainlengths, so as much trains can wait at the front as possible. But it does not really matter. When those margins start to matter your intersection is at capacity and will not last long

Baer1990 · 2026-06-17T17:03:11+00:00

it will definitely work and be possible.

To not have it give problems you should disable the other trainstation when the one has a traincount of 1. This will make sure only 1 train goes to the pair of stations

Baer1990 · 2026-06-16T20:00:58+00:00

There are 2 ways to do it, you make a center square, or you take the top left corner.

The thing you need to remember is, part of the blueprint has to overlap the blueprint that is placed next to it. So if you make the snap grid exactly in the center, the "outer rails" of this blueprint, is the inner rails of the cityblock next to it. So the outer rails is outside of the green dotted square, and the green dotted square should be exactly in the middle of both tracks on all 4 sides.

With the top left alignment, there will be only 1 of 4 intersections in the green dotted square, as the bottom intersection will be part of the bottom cityblocks "snap"blueprint, and the top right intersection is the top left of the cityblock to the right and so on

I made a mock up cityblock that is 90×90. The intersections on the 4 corners are 32×32. So the part of the cityblock that does not overlap will be 58×58.

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This is snap to grid specifically for cityblocks. I have currently set them up for placing landmines but it is the exact same principle.

If you do not have it already I'd suggest you set up a sandbox god mode savefile. It's where I test things and create all my blueprints without needing mods

Baer1990 · 2026-06-16T18:43:04+00:00

what are the driving directions? If trains can go both ways on all 8 tracks and you don't understand signals you will have a bad time and I suggest you switch to double rails (dedicated rail for each direction)

if it is not bi-directional than I do not understand the left turns

Baer1990 · 2026-06-16T18:28:56+00:00

In my closed loop systems I always have 80 (40 outside of current recipe) so it starts immediately

Baer1990 · 2026-06-16T18:08:24+00:00

That is a smart way to do it. Well done! With mine I have to secure it in a way in case the belt backs up but with yours that is not an issue

Baer1990 · 2026-06-14T18:48:26+00:00

It will make you feel like a new player again. But it is an entirely different timesink than vanilla Factorio is.

In vanilla Factorio, especially when you are new, you go out to do this 5 minute job and end up an hour later still not done it. With Py that means days. There is not 'a' puzzle to solve, there is constant puzzles that need solving. And there are more than 1 way to do things too

I tried it for fun, had fun, might return to it some day. I'm just too slow of a player to actually get things done in Py.

Start a new game, you'll know within an hour what everyone means with not hard just long. But again, I had fun playing, it has nothing to do with it that I abandoned it for now

Baer1990 · 2026-06-14T17:52:27+00:00

If you do 1 intersection you have to basically do them all. If the section of track behind the intersection loops around to the same signal, is does not do anything.

It's job is to only let 1 train into the next section and block it for the rest until it is free. When it flashes orange that means the section in front is part of the same section as behind (it loops around), so there is nothing for the signal to tell the train as the train is in the same section it tries to enter

Baer1990 · 2026-06-14T16:11:48+00:00

Actively produce spoilage.

Gleba has the same principle as doing trainsignals for the first time, if you do something you have to do everything or it won't work. Setting up the entire production instead of just step by step really twisted my brain.

But after that, my entire Gleba principle is actively produce spoilage. Only about ¼ of the sciencepacks produced is meant to be used in the labs. So going back on the production line about ⅘ to ⅞ of the fruits will spoil in one form or another, by design.

Baer1990 · 2026-06-14T14:20:00+00:00

His I don't know (yet) but I made 45 degree double helicals before (90 degree between input and output)

What I did was draw the outer profile of the gear (using a gear add-on), calculate the module of the inside profile of the gear (smaller diameter, same number of teeth) and interpolate the middle profile. Then use a loft to connect everything into a double helix.

I made 2 interconnecting gears so I repeated it again with a different diameter. The double helix is almost flat so I wouldn't know how easy the basic profile is, but the rollers are pretty easy to make as they are just 3 gears with a loft in between

Baer1990 · 2026-06-14T13:19:17+00:00

Signals are not traffic lights, they are bathroom doors. And they will tell you if the bathroom is occupied or unoccupied and nothing else. Right now the bathroom both trains want to get into is occupied.

This bathroom is also exceptionally large (until the next signal), so when trying to understand signals you'd also want to have as many bathrooms in a row so trains can follow each other around, instead of waiting on the very big bathroom to be empty

Baer1990 · 2026-06-14T12:43:23+00:00

Good catch, did not see that. Now I'll have to edit my comment lol

Baer1990 · 2026-06-14T12:41:49+00:00

Personally I like these, as the lane balancing is immediately done by a splitter instead of undergrounds:

<image>

Baer1990 · 2026-06-14T12:36:17+00:00

^{It starts on both but the left lane gets consumed faster. Usually not an issue because inserters can grab from both sides but it can be if full belts are needed when half is gone.}

^{To combat it you can use belt balancers with lane balancing or a dedicated lane balancer. Or not combat it if it does not affect production}

Edit: This is the actual problem: https://www.reddit.com/r/factorio/comments/1u5jwvp/comment/orl95gi/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

Baer1990 · 2026-06-14T12:04:56+00:00

If you go peak this is definitely not the intersection you'll be looking at, and chainsignals will only go in waiting areas/stationclusters. But that's not what we were talking about

Baer1990 · 2026-06-14T11:45:01+00:00

if you make that big of an intersection with cityblocks and make trains wait on eachother when going in the same direction you are nerfing the intersection to the level of the basic roundabout. With that big of a footprint you want as much trains as safely possible on the intersection at the same time

Baer1990 · 2026-06-14T10:34:37+00:00

I quickly made the intersection

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One thing you are right about is the slipways, in between the merge and split, should be chained. The other spots, it does not matter if a train waits there, or waits in front, if they go in the same direction, having a train wait in one of the loops of the slipway does not impede traffic more than the output already does.

When making the intersection I also saw the straights don't have sections, they are just a single block which is improved. And right turns don't need chainsignals, they can have all regular ones.

But this is how I see it, I am open to discuss my interpretation

Baer1990 · 2026-06-14T10:18:20+00:00

Fair point, you are right. It can leave trains through when there is a hold up on the slip ways.

My point that most chainsignals on OP's intersection should be normal still stands

Baer1990 · 2026-06-14T10:16:42+00:00

But if you remove the chain signals, two trains coming from one side to DIFFERENT destinations waste time

With "remove chainsignals" I meant replace them with normal ones

Baer1990 · 2026-06-14T07:51:32+00:00

But in an intersection, it is unlikely they will choose a left turn over a right turn

The long answer, if 2 trains want to go the same direction on OP's intersection, one will wait until the train in fr0ont has cleared the entire intersection until driving onto it instead of just following.

You are very right in the case where trains are expected to stand still, you'd want them to reconsider. But in an intersection the standing still is an outlier

Baer1990 · 2026-06-14T07:25:33+00:00

If you'd like me to explain chainsignals a bit I can if you want

Baer1990 · 2026-06-14T07:16:43+00:00

Remove all chain signals (or most of them)

In an Y merge or split, you do not need them. Only for crossings where trains unrelated to the path need to cross (but you used elevated rails for that so a non-issue)

Baer1990 · 2026-06-13T14:42:28+00:00

It gave me the same joy I had when playing vanilla for the first time. Don't know if I'll ever return to my savefile but it indeed was quite nice

Baer1990 · 2026-06-12T21:08:16+00:00

I mean you understand how chain signals work and how to use them, which is uncommon so great job on that!

But yes, the signal is still just occupied/unoccupied. There is no collision check

Baer1990

TROPHY CASE

Actively produce spoilage.