[13.15] [HanziQ] Chain signal before station lets train pass despite occupancy next block

[mickael9]

In the image below, the train crosses a red chain signal

chainfail.gif (756.5 KiB) Viewed 9153 times

[Nexela]

Well at first the flashing gave me seziours and I though it was signal placement. Then I confirmed it.

Turns out If there is a station between the chain signal and a regular signal the train will ignore the chain signal and go to the station as long as the part of the block between the station and the chain signal (the segment) is clear.

[mickael9]

Oh ok it's the station causing it, I thought it was some confusion between the two sides.

I also just noticed that the 2nd regular signal on the bottom turns red at the same time the chain signal turns orange.
I don't think this is supposed to happen either.
Edit : nevermind, that seems correct

[TruePikachu]

I'm not sure what the expected behaviour for this would be...

[mickael9]

Well, the correct behavior is what you get when you move the left stop past the chain signal in which case the train stops at the red chain signal as expected

[Nexela]

The correct Factorio behavior would be to stop at a red signal chain or otherwise

[TruePikachu]

The main issue, from a virtual railroader's point of view, is that one aspect is being assigned two different meanings:

GREEN - Block is empty, all next blocks are empty.
YELLOW - Block is empty, train approaching which will enter block.
BLUE - Block is empty, some (but not all) next blocks are empty.
RED (maybe change to ORANGE?) - Block is empty, no next blocks are empty.
RED (keep this one as RED) - Block is occupied.

Personally, I believe the train should be permitted to enter the block if it is empty and its destination is inside the block; I'll get a second opinion about this from a fellow railfan.

[Loewchen]

This setup does not show a bug imo, but you could test (I don't have access right now) if it is possible that the train could interfere with a junction between station and the next signal.
And if the rail from block signal to station is considered a dedicated block when the train is going to stop at the station.

[TruePikachu]

you could test (I don't have access right now) if it is possible that the train could interfere with a junction between station and the next signal.

It would cause the block to become occupied, so no other trains could enter it, by design. Putting 1-2 chain signals between the station and the other junction theoretically would cause the obstruction in the station block to be ignored, for trains travelling on said other junction but not with the station to proceed as usual.

With respect to train movement (trains ignore the displayed aspect, as OP demonstrates), the only difference between a chain signal and a block signal is that a train won't pass a chain signal if it can't pass the next (if applicable) signal in its planned route; the block signal logic still applies to them.

EDIT:

And if the rail from block signal to station is considered a dedicated block when the train is going to stop at the station.

There is no reason it would be, since stations don't determine block sections, and the blocks are enumerated when constructed and referred to through their ID numbers (I believe).

[Loewchen]

For the record:

1. the train does not cross a red signal.
2. the signal only gives way if the train does have a scheduled stop at the station in between.
3. the signal also gives way if the station after "base" is to the west.
4. the signal does violate the rule to only give way if the next block is unoccupied.

I am in doubt if this needs fixing though, as I could not come up with a setup with proper signalling were this would be an issue.

[TruePikachu]

I am in doubt if this needs fixing though, as I could not come up with a setup with proper signalling were this would be an issue.

In my opinion, the only thing that could need fixing is the aspect displayed when there are no exits from the block available, displaying either orange or violet (being adjacent to red in the color wheel; orange looks closer to red, but violet mixes in the blue aspect). This way, the two additional "restrictive" (i.e. not fully clear) situations the chain signal can display (some or all exits red) do not conflict with the builtin block signal's aspects; the train logic itself wouldn't need changing.

[Klonan]

After discussion with HanziQ, the trains behaviour is correct, the only thing incorrect is that the chain signal should show as blue, as some of the paths past it are open.

[mickael9]

Does that mean it will show as blue only if a train is trying to go to the stop or will it always be blue if there is a stop in the section regardless of the incoming trains?

[HanziQ]

It will show as blue when there is a station in the following block, followed by a red/blue signal

[impetus maximus]

i have to disagree with this being proper action for chain signals> station > signal.
here is an example of a test track i built to learn how signals/chain signals work.

screen shot

the train facing west on the main line at the stop went through the blue chain signal on the right.
this blocks the main line and locks up the turn around.

i realize this is not an ideal setup but if the chain/station worked as i expected, it would be a working system.

[HanziQ]

In the
(red, should be blue) chain > station > (red) chain
setup, if the train is going to the station in the middle, it is not (and should not be) concerned with the state of the signals following the station, that's how it is designed.
If it's continuing through, it will be concerned with the state of the signals. That's why it should be blue.

[impetus maximus]

i hear where your coming from. the blue state of the signal is great for trains finding a path to where it wants to go.
would be nice to have the option to opt out for a station. perhaps the option could be on the chain signal.

LOVE the game BTW!

[HanziQ]

Fixed for the next release.