Sunflower junction (8-way RHD unbuffered double roundabout; 11-car max)

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Theikkru
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Sunflower junction (8-way RHD unbuffered double roundabout; 11-car max)

Post by Theikkru »

As far as I'm aware, no-one's posted an 8-way junction. The lack of one's been weighing on my mind for a while now, so I sat down and made one. I'm not entirely convinced there's a practical necessity for such a thing, but here it is anyways:
Sunflower.png
Sunflower.png (701.43 KiB) Viewed 2530 times

Trains longer than 11 cars will crash into themselves if they try to make a U-turn, and I'm pretty sure this is one of those junctions that you can't swap to left-hand-drive without a significant rework, due to space constraints. Other than that, this seems to behave pretty well, based on my limited testing in sandbox. If nothing else, this can be pruned to serve as any X-way junction where X is less than 9.
Thoughts?
Last edited by Theikkru on Thu Oct 15, 2020 7:28 pm, edited 1 time in total.

Gamatron332
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Re: Sunflower junction (8-way RHD unbuffered double roundabout; 10-car max)

Post by Gamatron332 »

Beautiful. I want one but I have taken a hiatus from blueprints. But “my own” design will be similar ;). Have you found any throughout issues? (How many trains can it safely handle before a deadlock is imminent ) I can see this being used at the edge of a grid megabase where the grid stops and the trains become “screwy”

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Re: Sunflower junction (8-way RHD unbuffered double roundabout; 10-car max)

Post by Theikkru »

It's an unbuffered junction governed by chain signals, so it shouldn't ever deadlock, so long as the exit lanes remain unobstructed. I don't have a good way to measure throughput since there isn't a neat tool (like the 4-way throughput tester) that will work properly on this thing; there can technically be up to 8 trains in it simultaneously, but that's heavily dependent on what routes the trains are taking. I did try to minimize the impact of left turns.

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ickputzdirwech
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Re: Sunflower junction (8-way RHD unbuffered double roundabout; 10-car max)

Post by ickputzdirwech »

Theikkru wrote:
Thu Oct 15, 2020 12:19 pm
Trains longer than 10 cars will crash into themselves if they try to make a U-turn
Is that because they actually take a left turn/the inner circle when they do a U-turn?
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Re: Sunflower junction (8-way RHD unbuffered double roundabout; 10-car max)

Post by Theikkru »

ickputzdirwech wrote:
Thu Oct 15, 2020 7:06 pm
Is that because they actually take a left turn/the inner circle when they do a U-turn?
Yes.

I'm currently trying to redesign it so the trains entering the junction in a left turn don't block the exit to their immediate right...
OK I've fixed it so that the blocking no longer occurs. This had the side effects of moving the entrances/exits around and increasing the inner circle enough to accommodate an additional car.

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