Should public_transport=stop_position and railway=stop be kept separate?

harahu · 2024-09-04T14:48:47.827Z

I’m trying to figure out whether nodes tagged with public_transport=stop_position (on a subway) should also be tagged as railway=stop, or whether the latter tag should be on a separate node.

I feel like the wiki is ambiguous on this, as illustrated below. Which interpretation would you lend the most weight to?

Evidence against joint tagging

The railway=stop wiki page states that (emphasis mine):

It’s usually located adjacent to a platform at the places where the driver in the cab stops in any direction

Whereas in Key:railway - OpenStreetMap Wiki it is stated that public_transport=stop_position should be used in the middle of where the train stops. Note that the public_transport=stop_position wiki page says nothing about positioning.
This diagram, from the railway=station article, shows railway=stop positionally offset towards the end of the platforms, whereas Railway stations - OpenStreetMap Wiki shows public_transport=stop_position used centrally.
The wiki pages of neither tag mentions the other as a useful combination.

Evidence for joint tagging

Public transport - OpenStreetMap Wiki suggests using the tags together.
Railway stations - OpenStreetMap Wiki suggests using the tags together, both in diagram and in writing.
Tag:railway=halt - OpenStreetMap Wiki suggest using the tags together in a diagram.
iD gets mad at me for keeping the tags in separate nodes:

Screenshot 2024-09-04 at 16.47.54732×452 25.7 KB

alan_gr · 2024-09-04T16:08:28.783Z

As far as I know they are usually on the same node in practice, but perhaps there are exceptions.

The reference to the driver in the cab seems to have been added in September 2020. As “railway=” and “public_transport=” wiki pages are often edited by different people it is not surprising they are not in sync.

I don’t see how it is possible to apply either method consistently in any case. Maybe where all trains are the same length. But where train lengths differ, at least one of these positions must be variable. I would guess there is a lot of variation in practice.

On the absence of a “useful combination” reference - for the railway=stop page at least, there was such a reference at various points in the past. But at least one editor tends to remove references to public_transport tagging from railway= pages.

alan_gr · 2024-09-04T16:35:16.929Z

Also: according to taginfo, 99% of objects tagged railway=stop are also tagged with public_transport=stop_position.

The other 1% could in theory be cases where mappers have strictly separated the two definitions of the stopping position and mapped both. But they could also be freight-only stops, or simply cases where nobody has added public_transport tagging.

https://taginfo.openstreetmap.org/tags/railway=stop#combinations

harahu · 2024-09-04T16:45:00.921Z

When in doubt, trust the data. The numbers heavily suggest joint tagging. Thanks!

harahu · 2024-09-04T16:59:41.819Z

alan_gr:

On the absence of a “useful combination” reference - for the railway=stop page at least, there was such a reference at various points in the past. But at least one editor tends to remove references to public_transport tagging from railway= pages.

It seems this is @DaveF you are referring to. Since they’re invested I’m tagging them here in case they have something to add to the question at hand.

DaveF · 2024-09-10T18:10:03.700Z

There appears to be a lot of confusion about the relation between PTv2 & the original railway/highway schema. Worryingly this confusion extends to those who conceived the PTv2 schema.

Even though they tag the same objects they are separate schemas.

They are not dependent on each other.

For example, tagging an object with railway=station does NOT mean that the public_transport=station has to be added. In fact, there are many railway stations that aren’t used for public transport.

Those are the reasons why I remove references to PTv2 tags from various key:railway=* webpages.

Key:railway page should not contain any public_transport tags.

Specifically about railway=stop they should be placed where the engine stops, but I don’t really care as it will never be used.