[Tagging] Feature Proposal - RFC - [UPDATED] More Consistency in Railway Tagging

[Martin Atkins]

Hello again,

Based on the great feedback I got about the proposal I've updated in an 
attempt to address the following concerns:

- Representing multiple tracks with a single way doesn't make sense 
because trains can't "change lanes": I scrapped that part of the 
proposal in favor of a new separate-way-per-track tagging scheme 
described in the next point.

- Deferring the detail mapping to a separate proposal isn't good enough 
because there is already detailed mapping in the wild that needs to be 
addressed: I proposed a compromise that allows existing detail tagging 
to be adapted via a single tag change per way and no geometry at all, 
separating the concepts of "railway" (rail right of way) from 
"railway:track" (an individual track).

- Also filled out my initial detail tagging proposal with a scheme for 
describing the two-dimensional area occupied by the railway, based on 
the area:highway proposal. As well as providing a nice 2D outline of the 
railway right-of-way, it also provides a boundary to software that can 
be used to answer the question "should I use the railway or the 
railway:tracks?"... if an area:railway contains railway:track ways, they 
should be used in favor of any railway way by software that supports both.

I believe this proposal provides a way for the two levels of detail to 
co-exist in the OSM database and each be used in situations where they 
are most appropriate.

The updated proposal is in the same place as the old one:
http://wiki.openstreetmap.org/wiki/Proposed_features/Railway_Schematic_Mapping

I'd appreciate it if those who have participated in the discussion so 
far would take the time to review the updated proposal and let me know 
what you think.