Hi Erich,

Am 2015-01-28 um 00:37 schrieb Erich Pfistner:

One of the best data sources for mapping in the U.S. has been the Federal Railroad Administration's GIS Data http://fragis.fra.dot.gov/GISFRASafety/; and the most expansive data is the level crossing inventory.

Is the data quality of FRA as bad as the data about railway lines? Have a look at Pratt, Kansas (I randomly zoomed in and encountered the error). https://www.openstreetmap.org/#map=16/37.6406/-98.7490 If you look at FRAGIS (ArcGIS.js has no permalink feature there), you will see a red line between the railway line in the south and the line in the north through the residential area and houses.

Because other mappers (and I, too) consider copying data from Federal Railroad Administration as an import, you should ask OSM Import mailing list before adding a large amount of crossing information to OSM from FRAGIS. (No one would care if you copy a handful of crossing because you correct tagging of railway line, but if you start to add several dozens of crossings, people would scream "Import! Where is the discussion?" They will ask you how good the data is (have you checked quality in field?), how it is licensed (seems to be no problem), how you want to do it (workflow description; maybe source code of used scripts), which tags you want to use and, maybe, how you will keep the data up to date in future.

From my German point of view, I am 95% against imports because Germany is 95% import free [1] and has been mapped manually.

Are you really allowed to use these datasets? I have not found any page there which says how they are licensed? It would be a showstopper if the license is not compatible to OSM Contributor Terms.

There's a few things in there that are documented that don't have tags yet, and I think they are useful. They are:

• key=crossing:cantilever
  • Values: yes/no
  • Description: Metal cantilever that extends over the road, and
  usually has a crossbuck/saltire and/or flashing lights mounted to it.
• key=crossing:contact:emergency
  • Values: <string>
  • Description: A designated contact number for contacting emergency
  operators.

Is this number written at a sign at the crossing? If no, I would not map it and would prefer tagging a reference number instead which links to the database entry at Federal Railroad Administration.

• key=crossing:contact:railroad
  • Values: <string>
  • Description: A designated contact number for contacting the
  railroad.
  • key=crossing:contact:state
• Values: <string>
  • Description: A designated contact number for contacting state
  government.

I don't think that this should be mapped. Why shall I call state goverment in case of an accident at a level crossing? Don't copy the whole database. :-)

  - key=crossing:quiet_zone
  - Values: yes/no
  - Description: Locomotive engineers/operators are not to sound the
  horn at these crossings. There is often some sort of additional
  sound-producing device at these crossings.

I would prefer crossing:quiet=yes/no because zone sounds like a track section, e.g. one mile through a residential area where sensitive lawyers have their homes. :-)

  - Federal Railroad Administration page
  <http://www.fra.dot.gov/Page/P0689>

• key=crossing:traffic_signal
  • Values: control/interconnected/no
  • Description: In Urban environments, highway intersections and level
  crossings are often adjacent to each other and therefore the

level crossing is integrated into the traffic signal controller. "control" is to indicate a crossing where traffic signals replace the typical alternating crossing lights and other standard protections. "interconnected" is when the traffic controller program will alter from typical operation when a train is approaching. It could be a red light for traffic in that direction, a temporary no right/left turn restriction, or a number of other scenarios.

We have such traffic-lights-railway-crossing combinations in Europe, too. But up to know, there is no special tag.

  - key=crossing:wigwag
  - Values: yes/no
  - Description: Old type of crossing protection consisting of a
  pendulum swinging back and forth. There's approximately 100 left

in service in the U.S. - Wikipedia page https://en.wikipedia.org/wiki/Wigwag_%28railroad%29

Yes, wigwags need an differnt tag.

By day: http://youtu.be/ynKeE_XAWmM?t=57s At night (another crossing): http://youtu.be/coEvaOfTqOI?t=9s

Do wigwags show a red light by day? Is it bright enough bo be visible by day? If yes, you can tag crossing:light=yes.

In Germany, car drivers would probably overlook wigwags. :-) We still have lots of accidents at level crossing which have no barriers (in West Germany barrier-less crossing only have red flashing lights and saltires). https://www.youtube.com/watch?v=5l-WvUi_3Co https://www.youtube.com/watch?v=Eod_kJMHul4 http://youtu.be/PSW5vhliBBM?t=1m Such crossings still exist on branch lines on secondary roads and on main lines on small roads (like this track).

The inventory reports also list the count of crossing lights, crossbucks/saltires, and other such warning devices. I am unsure if these would be useful enough to tag, however.

I do not think that it useful to tag how much lights are mounted at the crossing. This number should be mapped if the mapping of this area is at a level where every traffic sign and street light is mapped. At the moment I see only two usecases for mapping each (flashing) light pole at a level crossing – train simulators and car race simulators with real data.

In addition, the integration of traffic signals at highway intersections with level crossings leads to a problem of grouping together elements of the entire junction, or even just the level crossing with itself. This is a problem with highway junctions in general. I think it could be a good idea to co-opt the complex junction relation from Proposed_features/Junction https://wiki.openstreetmap.org/wiki/Proposed_features/Junction. This would also allow level crossings of multiple tracks to be grouped together. They way I would structure it is:

• Relation tagging:
• key=type=junction
  • key=junction=level_crossing
  • key=ref:fra_crossing
    • Value: <string>
    • Note: While not an approved value, this is the value I have been
    using for marking the ID used in the FRA's Crossing Inventory.
  • Any of the tags used for the level_crossing node, as many of them
  are better applied to the relation than the node.
• Relation roles:
  • (blank)
    • Used on: Anything else
    • Description: Used to include anything else that isn't listed
    below. The only thing I can think of that could be is the

segment of track that is embedded in the roadway. I have tagged this in the past as key=embedded=yes/pavement/metal/wood/plastic (plastic includes rubber). The highway section between stop lines/traffic signals could be added as well, as I suppose those are part of the junction as well. - level_crossing - Occurance: 1 or more. - Used on: key=railway=level_crossing or key=railway=crossing - Description: This is where the railway track intersects a highway or pedestrian path. - traffic_signal - Occurance: 0 or more - Used on: highway=traffic_signals - Description: Any traffic signals that are part of this junction. This assumes that the traffic_signal is not mapped at the intersection of roadways. - stop_line - Occurance: 0 or More, mutually exclusive with traffic_signal - Used on: Nodes tagged with key=highway=stop_line - Description: This is where vehicles are to come to a stop, in cases where a traffic signal would not otherwise be tagged at this position. - location_hint - Occurance: Optionally one. Mutually exclusive with. - Used on: Any node. - Description: A hint to a renderer as to where a good place to put the the junction number or name on the map.

When designing ORM tagging scheme, Alex tried to avoid relations to keep mapping easy, especially for newbies. The railway mapping community is small, we should do everything to keep the entrance steps low. I suggest to use the methode introuduced by proposal "Tagging for complex junctions" in 2014. https://wiki.openstreetmap.org/wiki/Proposed_features/Tagging_for_complex_ju... Lets enlarge this proposal for combined highway-railway-intersections. I have mapped an example: https://www.openstreetmap.org/#map=19/49.14069/9.19136 An image taken from south of the level crossing: http://www.abload.de/img/05jef5t.jpg

Best regards

Michael

[1] Our largest imports are/were addresses in Cologne (still running for over a year or longer), Berlin (just finished) and Rostock (about 4–5 years ago), boundaries everywhere and WMS services of one large state and a few cities.