Discussed on mailing list, apparently already in use in quite a number of places.
This will indicate the number of railway tracks that a particular railway=rail (or similar) way has. Sidings, for example, would be modelled as railway=rail spurs with tracks=1; quad-track as tracks=4. This could be used by renderers for emphasising or widening quad-track lines.
Morwen 20:45, 14 June 2007 (BST)
- Would we want to specify that the default (if none set) is 1, or undefined? I'm wondering about the case where you have tracks=4 on both sides of a station, then split it out into individual tracks through the station, and how much tagging we'd require there. Gagravarr 12:08, 15 June 2007 (BST)
- Default is undefined. I'd thought about this case myself. We'd not want to model this as a Y-type feature, because there is no actual junction here necessarily, just an increase in detail, and we don't want to pretend that the diagonal part of the Y. I'd suggest having a way perpendicular to the railway line, representing the edge of detail, like so
|------> railway=rail tracks=1 oneway=yes -------->^ | | =============|------- railway=rail tracks=1 --------------------|=============== railway=rail | | tracks=3 v<------ railway=rail tracks=1 oneway=yes ---------| detail marker
In this case we have a an up line and a down line, and a relief line between them. The rails are exactly the same distant apart in both segments, it's just that one is being modelled as way-per-rail and the other as way-per-bunch of rails.
Just to make it clear, i'm not proposing this as part of this proposal; just indicating how I see this type of thing going. Morwen 12:46, 15 June 2007 (BST)
Why not just have a way for each track? --Hawke
- I have a fealing that in the near future this will happen and each track will be its own way. Because tracks are so striaght I don't think the amount of data required to do this is particually wasteful. There is nothing wrong with this proposal though, as sometimes 2 or 4 rails go side by side for hundreds of miles, so to tag it as double seems acceptable for a quicker way of doing it. A lack of a tag stating the amount of tracks should mean 1 track is asumed as default though I think, so that people that don't use this tag don't stop having tracks appear. Ben 01:58, 12 July 2007 (BST)
I agree that this would be useful. I'd vote for specifying a default, though. Robx 18:37, 18 January 2008 (UTC)
this appears very redundant: if there are 3 tracks, draw 3. if there are 28 tracks, draw 28. rather than coming up with ugly hacks to make one line display as 4, it would be better if someone came up with a plugin that automatically duplicates tracks, for JOSM. this already exists in merkaartor Myfanwy 20:00, 24 January 2008 (UTC)
- It is very difficult to map multiple tracks because they're so close together. GPS simply isn't accurate enough to distinguish between individual tracks, and neither are Yahoo satellite photos (although some high-resolution Google photos, which we can't use, are). I don't think it makes sense to map individual tracks given the accuracy of our current data; it's just like we don't map the edges of roads (unlike the OS) for the same reason. We should just use this tag to indicate number of tracks for now. Andrewpmk 20:05, 25 January 2008 (UTC)
- well, i've seen this done already on the map in south london, and i intend doing it in auckland (20+ tracks). we don't need to gps locate every track, just the outer ones, then subdivide the ones in between - that's what i'll be doing. Myfanwy 03:14, 26 January 2008 (UTC)