Topic 1: I had seen some interesting behavior where the name of an abandoned line was rendered even though it was not tagged in the way but was tagged in a relation. I also saw cases where a street was rendered with an abandoned line even though it wasn't tagged on the way but was included in the relation. I've also seen instances in the electrification layer where there's a double render: both the electrification color and a gray line appeared in the same location conflicting. Thirdly I've seen instances where the way and the relation were tagged 'abandoned' and the line showed up as solid rather than dashed.

It took me a while to figure out what was going on since I had seen ORM documentation that says we do not render relations. It turns out that the OSM backend turns relations into ways, assigning them a negative osm_id. ORM then renders these ways.

Basically, if a relation is tagged railway=construction/abandoned/razed/disused/rail/light_rail/tram/subway, it will render in ORM. There are guidelines that say don't use railway=rail on a relation (https://wiki.openstreetmap.org/wiki/Tag:route%3Drailway). Perhaps they should be expanded. Maybe even a validation rule should be added to the editors.

So the question I have is what's the best way to deal with these relations? For some the easiest thing to do is remove the railway tag from the relation. For others, the relation is so large (I saw one last night that was 500+ ways), and not every way is individually tagged that map accuracy would be decreased if the railway tag was removed from the relation. For those cases, it seems easier to de-tag a few ways and let the relation take over. But then if the way ends up being blank, I feel guilty and I then rely on others to not delete it and realize it's part of a relation. I also feel like I'm violating the rule of not tagging just for the sake of the renderer. Thoughts? Are there any guidelines?

Topic 2: The ORM renderer will shade in turntables and traversers if and only if they are polygons. Took me a while to figure out why some were rendering (like https://openrailwaymap.org/?style=standard&lat=40.87473288924837&lon...) and others weren't. It seems that a "closed way" (group of nodes joined by a line where the starting node is the ending node) isn't automatically a polygon unless certain tags are present. I'm thinking in the above case the tourism=attraction tag may have tripped the above case into a polygon. An area=yes tag will always force the database to create a polygon.

So the question is what do we do with all these turntables and traversers that are closed ways and not polygons? -retag with area=yes to force the renderer? I've done this for several but I'm not sure it's the right thing to do -request the OSM Project make a change so that a closed way tagged 'railway'='turntable' is treated as an area when uploaded. Not sure if this is a backend or editor issue. Is this even a backend thing or is it a local database thing? -have ORM render closed ways and areas/polygons. Not sure that's even possible with the rendered.

Thanks for reading, Jonathan