Population density, geographical point based pax origin and destinations
In 1.12 pax are spawned on specific geographical points, rather than by picking a station. And their destinations are also points in the map. Only after these points have been established are stations also picked, based on which stations can be reached from these points. Geographical points are picked based on population density. For now there is no visualization of these points so pax still just appear inside their origin stations, but the consequences of this previous step are very directly noticeable, specially when enabling the new "best path" mode.
Additionally, the way demand is generated has also changed. In 1.11 and earlier the achievable pax spawn rate of a given station was fixed, based on the station coverage. In 1.12 the pax rate depends both the population density around a station, and the reachable population from the station, subject to the distance demand curve. This means that opening more destinations in your network will not cut down on the desirability of the existing destinations as much as it did in 1.11.
All existing saves will see changes in their pax demand and generation flows, some of them very severe. A combination of changing the global demand % and the demand curves will help restore similar levels of demands compared to 1.11. For example, if more local demand is desired, you can change the destination curve to have much smaller % demand for 50km or more distances (less than 1%), then hike up the global demand %.
Overlapping station areas
Since pax now spawn on map coordinates, and they have a (player configurable, limited) capability of picking their origin and destination stations, it does not make sense to divide station coverage like in 1.11. In 1.12 station coverages can overlap:
Additionally, maximum station area radius has been increased from 1.5km in 1.11 to 2.3km in 1.12.
Points of interest
Players can now create special sign-like buildings which add some amount of population to a point in the map:
These signs count as population points, just like the built-in population texture. They can be used to for example liven up areas which see high demand in real life but have low population, like airports.
Mod POI layers
In addition to player created POIs, mod authors can also provide map mod POI layers. Players can subscribe to these mods to immediately layers of POIs to their game map. These layers can be hidden, or have their proposed demand curve altered by players if desired.
Multiple, player customizable demand curves
To make the new POI feature even more powerful, it is possible pick a different demand curve for each player created POI, or globally for each mod POI layer. This allows to define POIs which have a different time based demand curve, for example a stadium only being active for a few hours a week, but having an outsized effect on its nearby stations by combining it with a large population value. Or making the distance demand curve of an airport much less dependent on the distance, compared to the default curve.
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For more information check the blog posts:
https://carloscarrasco.com/nimby-rails-february-2024/
https://carloscarrasco.com/nimby-rails-march-2024/
https://carloscarrasco.com/nimby-rails-april-2024/
