Factorio Forums

disentius wrote: ↑

Thu Dec 03, 2020 6:46 pm

yep. needs an extra chain signal at the entrance...

Irony can be pretty ironic sometimes.

disentius wrote: ↑

Thu Dec 03, 2020 6:46 pm

yep. needs an extra chain signal at the entrance...

That was my first thought too, but there is an edit in the original post: (viewtopic.php?p=519620#p519620)

[EDIT] There are chain signals at the entry, of course, but they're behind the path, so that the path stays free, if the train has to wait

I experimented with removing chain signals in some situations and found that this reduced the ability for trains to make local fine grained decisions. In dense throughput scenarios, more chain signals tend to be better than less. Rail signals, I find, tend to be the biggest problem.

"Poor junction design" seems to be another way of saying, don't be ambitious about dense throughput. All well and good, but when you're fighting biters in DW type scenarios, land comes at a bit of a premium.

If I understand correctly, in summary: If you have a rail system where trains cannot stop or be backed up on the main rails for extended periods of time, then all but one of the chain signals in intersections are unnecessary since any train that enters the intersection will be able to leave in a timely manner regardless of whether they have the block out reserved ahead of time.

The problem with this is that in the larger picture, just as locally to a single intersection you can have a deadlock if 4 trains arrive at a cross at exactly the same time, and no entrance has a chain signal, you could also have a superdeadlock between multiple intersections since they all block the main line that needs to clear to clear the previous intersection, like this:
Or perhaps I am missing what you are suggesting.