Load Balancer/Shift Mainline

[bencookman]

Hi all

I have been studying the networks constructed by the openttdcoop group, which are simply amazing in many cases!

However, I have a question about the shift mainline/load balancing system. In the screenshot attached the empty wood train has taken the junction to move to a track further out in the mainline. Why has it done this? What is the logic that tells it to shift to the right, even if its route straightahead is still free?

Think it's a great method to gain efficiency, but I'm puzzled how it works!

Thanks, Ben.

[XeryusTC]

The point was to let mainline trains switch mainlines so one lane gets rather empty for trains joining the mainline so they don't have to wait for that long. It is all explained on the SML page (R&D section of the wiki) too.

[bencookman]

Hi - thanks for the pointer towards the wiki. I already realised that the purpose of the shift mainline design is to move trains away from the merge line, to make room for the joining train, but my question was more specific: the train in the screenshot has chosen to shift to the next mainline outwards, but I want to know WHY it has chosen to do that, because its route straight ahead is clear, so I would have thought it would have continued straight ahead rather than switching to the next mainline. Can anyone tell me what is within the game's programming which tells it to shift lines, even though its route straight ahead is clear?

Thanks again.

[SoLo]

I found that when making cross overs like that between the two lines. If there is a train up ahead, even if there are a few green signals between the lead train and the cross point, the train will switch lines because the other side is clearer. Might just be something with the path finding. The train sees more green on one line then the other so it takes it assuming that it is the better choice.

[bencookman]

Just a thought - perhaps it is because of the "fake" cross-overs on the straight ahead route which act as "barriers" and make the train think that the option of switching to the other main line is "clearer". Is that the case?

[XeryusTC]

There are single tile stations which add a penalty to the route straight ahead, so trains will try to avoid that route and take the other lane.

[bencookman]

Perfect - thanks for clarifying. I can now see that the station contains the "void" grf from your new graphics set. I hadn't spotted that the station was there when I posted my question. Explains everything!

Cheers.