Factorio Forums

The question is really about the specific meaning of the text on the wildcard signals. To give a concrete example, we have:
It says it will match the first signal that passes all wait conditions. I'm assuming it means the wait conditions for the interrupt. If so, then consider the following interrupt with conditions and subsequent signal usage.
This seems to say that if either copper or coal are received as signals with a value greater than 0, then copper (first signal), or coal (first signal that passes the wait signal), would be used to replace the wildcard in the station lists, thus sending the train to the copper or coal mine, and subsequent drop points, on demand.

This actually works, so that's great, but I think it's partly an accident. The signal list going into the station for a given train to interpret looks like this:
So - once coal appears in the signal list, the train evaluates the wait condition, but the signal used to replace the wildcard isn't the one that matched the condition - as claimed in the UI - but the first signal received at the station.

I actually thought this was working - but when setting up a separate stations to receive fluid jobs and processes them, it correctly takes the job at the point water appears in the signal list, but the signal is replaced by coal, not water.

The signal list is the same for that station and train, but the interrupt is switched to hopefully pass the matched fluid signal from the condition list.
So - should the game function as the description implies; i.e. the game has a bug, or is the description wrong; i.e. the description should be fixed ?.

Attached is my save to test this signalling feature.

I appreciate that this can be fixed by erecting long intricate electricity lines to keep the fluid and item signals separate, and in Space Exploration I can solve it using radar channels. I had hoped it was possible to solve the challenge elegantly following the wildcard signal descriptions, but either I'm missing something or there's a bug.

So - I tried this as an alternative - following a suggestion that the condition should include the wildcard, but if that's the case, I'm doing it wrong ...

The description is talking about two different things, you can use the Signal parameter wildcard inside a condition and the wildcard will assume a signal that clears all conditions you set if such a signal exists.
On top of that the wildcard can also direct the train to a station that has that signal in its name if you use the wildcard in the interrupt target station name.

You are not using the wildcard in any condition so the first method is irrelevant, you are using the wildcard in the target station names and from what I see in the screenshots, that should work but you are not showing the created temp stop.
Nothing in the description seems incorrect to me, it is just very brief.

Thanks for trying to help.

Both interrupt setups create the same situation:

Tried the condition elements the other way around in case that would help. Same result.

Tried this also .. no joy

Assuming there is a stone signal I do not see anything wrong with this. What else are you expecting?

There is a stone signal.

The wildcard signal seems to imply that it will match the first signal that passes the wait conditions. To me, it looks like only water should actually pass the wait conditions. So I expect my train with fluid wagons to be able to be controlled to only go to fluid stations when one of the signals is a fluid, and the actual fluid selected would be the one that passes the wait conditions.

I could create a huge set of decider combinators, one per fluid in the game, to filter out all fluids from the list of incoming signals. This then works. But then, what is the meaning of the text on the UI about selecting the signal that passes the wait conditions. Which conditions if not the conditions for the interrupt.

Is it possible to achieve where it picks the signal I want from the incoming signals another way, or will it always pick the first?

SpoonUnit wrote: Sat Nov 08, 2025 1:18 am The wildcard signal seems to imply that it will match the first signal that passes the wait conditions.

You are not using any signals in wait conditions.

Huh. OK. This could be the issue. So ... what would that look like? I was thinking that the signal coming into the station was being evaluated against these conditions, thus the qualified as signals in wait conditions.

How can I incorporate a signal in the wait condition then?

I see the 'signals' section. Will play.

I can't define a signal like A to equal water, so I don't see how using the letter signals could work. Is there an example somewhere of how this is intended to work? I feel like seeing one, or possibly multiple, examples of these wildcard signals in action would really help.

If I try this, I still don't get the B signal, which should be the signal passing the condition. I still just get the first signal, A, from the incoming signals.
These are the signals in this test:

SpoonUnit wrote: Sat Nov 08, 2025 1:54 am If I try this, I still don't get the B signal, which should be the signal passing the condition.

When using as wait condition, you still have not set any circuit condition as wait condition.

OK.

Where should I set wait conditions?
What does a circuit condition look like?

I'm clearly misunderstanding the absolute basics here, so it's no surprise I'm failing.

Just noticed the term 'wait condition' here.

For the moment, forget the wildcard popup description. Just remember what we all observed as game behavior. This thread and all other observations.

This actually happens:

• when the game engine is about to check and process the interrupts, before processing the first interrupt, it creates one replacement for each of the 4 wildcards and stores these 4 replacements.
• for the circuit wildcard, it looks into the current circuit connection of the train(**) and selects the 1st signal according to the internal signal order(*) as replacement. If there is no signal, the wildcard gets no replacement.
• for the cargo wildcard, it creates a unified inventory of all cargo wagons and selects the 1st item according to the internal signal order as replacement. If there is no cargo, the wildcard gets no replacement.
• for the fluid wildcard, it creates a unified inventory of all fluid wagons and selects the 1st fluid according to the internal signal order as replacement. If there is no fluid, the wildcard gets no replacement.
• for the fuel wildcard, it creates a unified inventory of all locomotive fuel slots and selects the 1st item according to the internal signal order as replacement. If there is no fuel, the wildcard gets no replacement.
• now all interrupt triggers are checked one by one with any wildcards replaced with the corresponding replacement found above. Interrupt conditions are checked, and if one matches, the corresponding schedule is inserted with the same replacements.

(*) internal signal order: in the item picker, ordered from left tabs to right tabs, from top to bottom, from left to right. Highest is wooden chest 1st on left tab, lowest is wube icon on bottom on last tab.
(**) it's the circuit connection of the train, not of the station. The train is only being supplied from circuit wires connected to the station if the train is still connected to the station. In case a train is in "destination full" or "no path" condition it's not connected to a station, so any interrupt checking for "destination full or no path" condition isn't working correctly if also checking for a circuit condition.

If you see it this way, it all falls into place and you will understand how triggers and wildcards will work.

Now create a description yourself and you will find it's extremely difficult to find a short one that's explaining this. It's quite possible you end up with the current one.

Tertius wrote: Sat Nov 08, 2025 9:47 am Now create a description yourself and you will find it's extremely difficult to find a short one that's explaining this. It's quite possible you end up with the current one.

Thanks for taking the time to explain this in detail. For the signal wildcard then, what you say suggests the following would be a more accurate and shorter description than the one currently present:

------------------
Signal parameter

Special Wildcard Signal
When used in schedule interrupt conditions and target station names, it is replaced with the first signal at the connected station at the moment of interrupt processing.
------------------

Is this incorrect, or missing a nuance? If not, this would mean the current description, which talks about replacing signals based on wait conditions, is misleading (at least to me) because, by the time wait conditions are evaluated, the wildcard processing has taken place and won't change again, and the target conditions and wildcards have already been replaced.

Loewchen wrote: Sat Nov 08, 2025 2:12 am

SpoonUnit wrote: Sat Nov 08, 2025 1:54 am If I try this, I still don't get the B signal, which should be the signal passing the condition.

When using as wait condition, you still have not set any circuit condition as wait condition.

I tried to incorporate the wildcard signal into a wait condition, but, as can be seen, the replacement in thet target station names using the first signal in the list, not the signal that passes a wait condition, has already taken place.
I'm clearly doing something fundamentally wrong still, but I'm just fishing around in the dark really. Was this the wrong way to use the wildcard in the wait conditions? Is there a way in which a wait condition evaluation can be used to achieve the outcome stated in the tooltip?

Incidentally, why does it evaluate Coal(1) as equal to Iron(1) here?
Do I need to, in some way, pass through the result of a wait condition evaluation in one interrupt to another waiting interrrupt condition?