OpenStreetMap
railway main line tagging
Posted by jaimemd on 25 January 2014 in English. Last updated on 25 August 2015.Dear Friends around Ekaterinburg,
I removed a lot of service=trunk or service=regional entries from railways beause this makes them completely invisible in ITO’s railway tracks map http://www.itoworld.com/map/14?lon=60.85148&lat=56.75938&zoom=9&fullscreen=true&fullscreen=true Also I added tracks=*
The lines to Kamiensk-Uralski and Tscheljabinsk were the first ones I edited.
I hope this did not lead to any damage. If yes I will try to fix it again. Both tags do not appear in the osm wiki while usage=main is recommended for main passenger lines. The rendering in Mapnik or standard view ist apparently not affected by my changes.
The tracks=* seems a bit tricky since it can apply to different situations. So one line can represent several parallel railway tracks. On the other hand there can be a single track railway line be parallel to one or more spur railways. I used this tag in order tell in which way the line is operated. So tracks=1 means a train must wait somewhere if a train in the opposite direction needs to pass. I used tracks=2 if there is one track for each direction irrespective of being one or two ways drawn. I left tracks missing for some large stations and intersections.
Discussion
Comment from RM87 on 25 January 2014 at 21:20
Try to avoid tracks key as it is controversial. There is no way to tell whether this tracks=n is a total number of tracks or there should be n-1 more undrawn tracks beside this track). Wherever possible simply draw out all tracks and tag them as appropriate. Bing imagery near Jekaterinburg is mostly good enough to draw all tracks out.
Comment from jaimemd on 29 January 2014 at 14:35
controversial hopefully means that we can strain for a useful solution. This is in my opinion of course not tagging tracks=n for telling that there are n-1 undrawn tracks. This should be looked up by the mapper using the osm-editor. If I map 60 buildings in a villiage which has alltogether 100 buildings I just leave the remaining 40 for someone else or a later time maybe leaving a note or fixme.
The numer of tracks of a railway line I find very meaningful and there are many examples in Great Britain or Sweden where the tag is used to mark tracks as belonging together to the same railway line.
As a side effect it can of course substitute a not drawn second track. Drawing this can be very boring and time consuming particularly in areas where nobody might zoom in so far that the second track can be distinguished. In contrast the above mentioned ITO-map provides information which can hardly be found anywhere else.
Comment from iWowik on 29 April 2015 at 13:06
You shouldn’t set tracks=2 on single track ways!
Here is some example (single track bridge) http://www.openstreetmap.org/way/103744403
Remove your fake tags from OSM.
Comment from iWowik on 29 April 2015 at 13:18
I see you also delete such valid data as service=trunk, usage=main. Stop this vandal actions and revert such your changes.
Comment from jaimemd on 29 April 2015 at 13:33
Would you pleas also send an example of service=trunk or usage=main - preferrably by message? I remember this being rather complicated. Maybe something really went wrong.
The bridge clearly belongs to a double track railway. And its a quite useful information displayed on http://www.itoworld.com/map/14?lon=17.67444&lat=60.17125&zoom=10&fullscreen=true&open_sidebar=related_menu
Comment from jaimemd on 29 April 2015 at 13:45
iWowik: Could you pleas mention an openstreetmap wiki entry or something similar which explains the use of service=trunk or usage=main?
Comment from iWowik on 3 May 2015 at 21:31
Very well! You delete tags while nothing knowing about it. Such questions are better before actions.
http://wiki.openstreetmap.org/wiki/Any_tags_you_like http://wiki.openstreetmap.org/wiki/Key:service service=User defined
http://wiki.openstreetmap.org/wiki/Key:usage usage=main
Comment from jaimemd on 7 May 2015 at 19:53
Hi,
the information about usage=* is not very detailed and may conflict with official classification of national railways. There lines might be classified by signalling systems and other regulations for construction. Also they are not used consistent in osm: Parts of Novosibirsk - Novokuznetsk are tagged as branch while the single track line through Bratsk without long distance traffic is tagged as main. service=trunk is missing completely on the wiki.
I did not find the places where I wtongly deleted the usage or service tags. I recently eorganised ways in the Kurgan station which is very complicated - starting with double but incomplete entries. I do not like to delete entire ways, rather cut them into peaces when necessary and reorganise the attributes of the parts. Maybe the deletion happened in such a situation. Than those tags should have been reappeared on the right place.