Airports: runways must now have a space around them

[jamespetts]

From to-morrow morning (the 20th of January 2020), all runways built in Simutrans-Extended will not be able to be placed next to any other object other than a perpendicular taxiway or runway. This will not affect runways and objects that have already been built.

The intention of this is to make airport construction more realistic in terms of the amount of space required. In reality, no buildings, roads, taxiways or runways are ever immediately adjacent to a runway.

[Matthew]

James, this is a nice new feature.

BTW I also want to say thank you for the bug blitz over the weekend. You prioritized tackling the backlog of issues over adding new features & improvements. I know multi-million pound game studios that aren't disciplined enough to do that! I know it's less fun for devs, but if I was speaking selfishly, as a player I'd prefer bugfixes any day. Happily we've got both! 

[jamespetts]

Splendid, I am glad that this makes you happy!

[Mariculous]

Whilst in general a good feature that will add-up more realism to the game, the planned rail tunnel underneath the runway won't work now either :/
So maybe it should be designed with an exception for the underground.

Anyways a nice feature.
The impressive bugfixing sprint last weekend was indeed even nicer!

[jamespetts]

I did intend to allow for tunnels under runways (but not tunnel entrances next to them), and I believe that I allowed for this in the code: does this not work?

[Mariculous]

No, it doesn't work.

Edit: It does work as long as placing the tunnel as a whole, instead of ctrl placing the tunnel portals and afterwards attempting to connect them under ground.

Further, building a tunnel portal next to a runway will fail but will not raise any error message.
Generally there seem to be quite a lot silently ignored cases that will disallow construction but won't give any respone.

[Vladki]

Something is wrong. See stephenson-siemens game, Gosish airport. I cannot extend the runway to east. I could build two tiles but can't join with the rest of the runway. Also I cannot build any taxiway towards north. I even cleared trees around, and raised land, but it did not help

[jamespetts]

Thank you for the report. I believe that I have fixed this; I should be grateful if you could re-test with the next nightly build.

[Vladki]

This seems to be only partially fixed. I can attach a taxiway at (561,66), but cannot at (562,66), and (562,67), and I do not see any reason why?

Also airports in real world have taxiways attached diagonally as well, which is now impossible.
Should I redesign the airports in the demo game to comply with the current restrictions?

And one more thing - it would be nice to allow one-way signs on runways, or otherwise forbid airplanes from turning around and rolling back on runway, instead of taking the nearest exit. (with the only exception of allowing turn around at the very beginnign or end of runway

[jamespetts]

Thank you for the report; I believe that I have at least mostly fixed this now. I should be grateful if you could re-test with the next nightly build.

[Vladki]

I will test, but could I ask for a simuconf.tab switch do disable the safety range? Just like it is possible to turn off air control towers. It badly affects games that started before this restrictions. E. G. I can't upgrade a rail track that is next to runway, both built before this restriction was implemented.

[Mariculous]

Building tunnels underneath, hower was not fixed. It's still not possible to build tunnels in sections.

[Vladki]

A new save of demo game, with modified airport layout that takes into account the current restrictions is here:
http://list.extended.simutrans.org/debug-saves/britain-letiste.sve

[jamespetts]

I believe that I have now fixed the issue that was preventing tunnels from being built under runways - I should be grateful if you could re-test with the next nightly build.

As to diagonal taxiways, I wonder whether it would be possible to permit these, but I am not sure quite what a diagonal equivalent of ribi_t::is_perpendicular would be, and such a method would be necessary to allow for this.

[Vladki]

James, as you said in game chat, that airports near cities had to close down and relocate far away. How about making those restrictions valid only for high speed runways (asphalt), and leave grass and tarmac runways without restrictions?

[jamespetts]

I have now pushed a modification that allows upgrading existing runways even if they would not be valid if they were built new.

As for allowing building for lower speed runways - the reason for the clearance requirement is not based on the speed of runways: no runway, to my knowledge, ever has any building immediately next to it or any taxiway, road or other runway running immediately parallel to it.

[Mariculous]

Does not seem to be entirely true and it seems we need to support slopes for runways too
https://basecamptreknepal.com/wp-content/uploads/2016/06/Lukla-Airport.jpg

However, note that the airport on the image was often refered to as the most dangerous airport in the world, so I guess it's fine.

I had some further reading about ICAO regulations on runways and 30m safety area around the runway is the requirement for the two smallest classes of runway, so It's perfectly fine.
Tha largest class, I gues required for A380, would even require 150m but that's absolutely impractical ingame.

However, as Vladki mentioned, it's fine for new games but should not affect old games as it simply makes upgrading of such airports entirely impossible. If one had known this before, one had saved the required space around but this way one will need to build a new one somewhere in the middle of nowhere.

Also note, that the tunnel bug still exists, which makes rapid transport for airports quite difficult.

[jamespetts]

Thank you for your feedback. As for the tunnel issue, this I fixed only a few hours ago, so it will be in to-morrow's nightly build.

[Vladki]

runway upgrade seems to work, but upgrade of other ways that already exist next to runway does not... (stephenson - siemens, ferninglock station)

[jamespetts]

I have just looked into this somewhat briefly - this looks as though it is likely to take a lot of work to deal with as data about whether a given tile of building is an upgrade is not available on the current algorithm when checking whether there is a nearby runway. Given that this is only a transitional issue, I cannot make this a high priority at present. If anyone else would like to work on this, I should be happy to incorporate a working fix.

[Mariculous]

James, I guess you are better removing the latest changes that allowed upgrading of existing ways and instead disable the runway distance feature for old savegames entirely i.e. store a flag to enable this in the save.
The changes now seem to allow building taxiways parallel to runways in some bugged way. (see Turningford International)
I somehow even got parallel runways built but don't know how exactly I got this done.

I really like the feature and already changed a few airports to fit the new requirements but for some it's still impossible, which is not a huge problem for the airports themsevles but it is imho an issue that these airports will also affect existing ways around the runway.
So the easyest way to handle this should be disabling the feature entirely for old savegames.

[Mariculous]

We have a crazy farmer on stephenson-siemens who decided that he doesn't care about airport security rules and will just use the spare area for fields.
Airport administration has already made a report but so far the farmer did not remove these fields.