Redesign the entire railway system. Again!

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mrvn
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Re: Redesign the entire railway system. Again!

Post by mrvn » Tue Jul 02, 2019 1:40 pm

mmmPI wrote:
Mon Jul 01, 2019 1:25 pm
I feel a bit sorry for ssilk because i can only notice what i disagree with some of the post while lots of it is quietly approved and is the basis for further reflexions.
Don't get me wrong. I agree with a lot of what ssilk says. The problem is the math is soft since a lot of it lacks values for constants or is just pseudo code. That leaves a lot of freedom to weigh parts and leaves the end result pretty much open for interpretation. I'm just going by experience.

It might even be that ssilk watched his train network at saturation X where more small trains would be better and I watched my train network at saturation Y where fewer larger trains would be better. We both could just be looking at different parts of the curve or the result might differ on the network design much more. That part has been mostly left out so far.
mmmPI wrote:
Mon Jul 01, 2019 1:25 pm
mrvn wrote:
Mon Jul 01, 2019 1:29 am
So you see, shorter trains are actually longer.

And here is another factor towards the chaotic:

The reserved length and breaking force aren't linear. Going faster isn't always good. In fact there is a optimum speed and if you go faster the space between trains increases more than you make up for by going faster. Trains at max speed transport fewer goods than optimal.


I was conducing experiments to understand how the previous part applies in the game and I am not sure how to understand "R" anymore,

Can 2 trains reserve the same block ?
2 trains can be in the same block, e.g. when you place them there. But they can never reserve the same block. The second train trying to reserve a block will fail to do so and start breaking.
mmmPI wrote:
Mon Jul 01, 2019 1:25 pm
In the case of a X junction, the middle crossing track, can be the last "R" of a train that goes fast and has a lot like 7 so it means in 7 units of time it will physically be there if it keep same speed. While at the same time the same block can be the first "R" of a another train that is only 3 block long.

Next unit of time the loco of the 3 block long train is physically at the "R" crossing, next unit of time another loco occupy the block physically , next unit of time a cargon wargon. then 3 units of time with nothing, then 7th unit of time after initial situation the first train first loco is physically present at the block.

Would that makes any of the two trains slow down and not happened as describe ? I am unsure how to test the set-up in the game.
As said above, two trains can never reserve the same block. So as soon as the first R of the second train host the X junction the breaks will apply and reduce the Rs. Worst case the train stops at the signal and has 0 Rs. If the X junction clears before that then the train will reserve the block and accelerate again. This causes the first R to move into the X junction as well as adds new Rs at the front.

If you want to visualize it then think of a little locomotive connected to the train with a rubber band that can stop instantly. When the train accelerates the little locomotive pulls ahead and stretches the rubber band. When the little locomotive hits a red signal is stops instantly and the real locomotive will break so as to not run over the little locomotive.
mmmPI wrote:
Mon Jul 01, 2019 1:25 pm
I see that the same idea that mrvn pointed out about reserved lengh being non linear.

I have made some setup in creative mod to visually depict the "jam" thing, you just have to turn on/off the constant combinator to run a setup, the 2 first I use to see the differences of traffic flow and roughly it shows when and how trains start to slow when they can't reserve blocks, up to the point where some of them are completly stationnary, like in a real traffic jam and it's propagation in the opposite side of the normal rotation of train, and also some of the slowest speed they can get before reaching the point of complete deadlock.
When you hit stop-and-go traffic then it's not the trains that move. It's the holes between the trains moving in the opposite direction. :)

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