I'm not quite sure whether this is a reported issue. One finds a lot of things when one searches for (chain) signal issues. What it looks like: a train passes a chain signal with two exists of which one is green and the other is red and the stops at the red one. In pictures: Factorio 0.15.11 18_5_20...

In your first pictures it looked like the right pump above the train does not connect or cannot connect to the tank on the right. I thought you meant this one. Anyway now I know what you mean. :) Hm. Can you put the left pump above the train one tile to the left? Maybe this helps. Looks like a bug ...

To clarify: This is what happens if the pump in the north is not there when the train arrives: Factorio 0.15.10 16_5_2017 0_37_39.png This is what happens if the pump is there Factorio 0.15.10 16_5_2017 0_02_59.png This is what happens if both pumps are there and the train with water arrives: Factor...

I have the feeling that each tank of my train selects a pump upon arrival and refuses to change its' mind even if this pump is off while an other pump is on. Some pictures. The selected pump south of the train gets enabled as soon as the train arrives (as soon as the circuit reads petrolium from the...

Hmmm... yes I can see that they are connect at the 'beginning', not sure how that happend though (this line has been supplying petroleum for some time now). Sorry to have wasted your time.

Here you go. The save file was created in 15.6 but I tested it with this file in 15.9 before reporting the issue.

Greetings!
I have a train with 3 separate tanks. When it empties the tank with Petroleum completely, it connects all 3 tanks. You can see it in the video below.
It may have something to do with the circuit at that station: i have changed it recently and this is the first time I have this issue.

Hmmmm... yes, I have to agree. It is not compatible with the system. Maybe it would be better to enable/disable a signal by the circuit all together, which is already implemented: it happens when you (de)construct a signal. [Edit: this can be done by using this mod https://mods.factorio.com/mods/jus...

Have an option to make a signal green if some condition is true. This will potentially lead to collisions, but only due to active choices made by the player. This would allow someone to 'program' his own logic for how trains behave.

To have more flexibility and creativity in use of electric power one could do the following. Introduce, additionally to the current electric poles, red and green variants of each pole. The poles will auto connect to the poles of their own color only. The circuit wires from one pole to an other shoul...

This has been a couple of times (including once by me :P ). The possible shapes are a torus, a cylinder and a Klein bottle. I have included the links that I could find. The second one makes a valid point: this could add a better way of balancing placement in a MP game. I would like to see such a fea...

Maybe, as a compromise between having this feature and not having it, it should be made possible to read the content of pumps. Pumps are are already connectable to wires and thus it might be easier to do for the developers.

Remapping the zoom in/out buttons changes the way you zoom in the normal view and on the map, but not in the train preview. You always need to use mouse scroll in the train preview window, independent of your settings. I think this is inconsistent.

Yes, same here. Many times I wanted to use a virtual signal as the second operand, but it's not possible. It should be possible, but that's a different suggestion I guess. For the second one: Yes, I want it to be true when i have exactly one signal. I could put a lamp connected to a box and set eve...

Tanks are the boxes of fluids and pipes are the belts, so let me pose a very suggestive question. If it is enough to read the contents of boxes, why make it possible read the contents of belts? It could be useful to avoid fluids going in to pipes where they should not be, without the need of placing...

I've had to build a "for loop" to extract one (arbitrary) signal and its value from an unknown set of signals. The fact that the values might reoccur was not a problem. Here's how I made it happen: the set of candidate signals (input) was from a known alphabet. For example, your alphabet ...

Most for-loops I know run in to trouble when two signals have the same value. Most are either very slow or conceptually complicated. I do think that 'one by one' for-loops over all available signals would get simpler and thus make new things possible. To me it seems a bit artificial, since the tie b...

I agree that some kind of filtering of single signals should be possible. I have had cases where this would be useful.
The lowest/highest matches would be nice to have, but are not a necessity. Once one can filter signals, one can build a for-loop that goes over all the signals and finds the maximum.

Letting trains go backwards to stations may not be so nice. See viewtopic.php?f=71&t=26719 .

There used to be a mod for that: viewtopic.php?f=92&t=15152. I'm not sure whether someone is still working on that.