On Fri, Jul 14, 2017 at 07:01:55PM +0200, Michael Reichert wrote: Hi,
> There are two open questions regarding the definition: > - What qualifies a track to have highspeed=yes? Minimum speed, curves, > type of traffic, fencing, train protection etc. are the relevant > factors. But it has not been decided yet which of them are relevant and > which are more important. > - If a track qualifies to have highspeed=yes, should the whole line > (including the slow sections at its beginning and end where it leaves > the older parts of the network or runs through existing stations) get > highspeed=yes? > > I would like to keep the discussion to the second question. I don't think you can answer the second question without answering the first. You could make an arbitrary decission about the second question of course but I don't think this would end discussions and also any decission about the second question limits the choices for answer #1. > > Presumably when exact speed limits will be mapped in the ideal case > > what is the use of this tag? > > Different countries define "high speed" different. In most countries > high speed traffic needs a more sophisticated train protection system. > The maximum speed of the less sophisticated train protection is often > but not always the border between "high speed" and "not high speed" > because the railway operators introduced the better train protection > system when they build their first high speed lines. > Countries with a large high speed network might set the limit higher > while countries with a smaller (or slower) one might set the limit > lower. The first one might be France, the second UK. Swiss railway staff > would experience 200 kph as fast (Olten—Bern, New Gotthard Tunnel). Do > we have fix definitions of highway=* all over Europe? No, we don't. Just > compare highway=trunk in UK with German highway=trunk. So basically you want a tag saying "this is considered highspeed locally"? Another aspect is the use of tilting trains. They are built to operate with speed considered highspeed on tracks which would be otherwise unsuitable for such speeds. Here highspeed=yes is too vague as it could mean any of highspeed tilting trains on curvy mountain railways or highspeed trains on dedicated tracks. > Map style authors are happy to render high speed network maps without > checking the location and the local definition of each line to be > rendered. The tag highspeed=yes is intended to be the extension of > usage=main/branch upwards. An early version of OpenRailwayMap tagging > scheme in 2011 suggested to use usage=highspeed but others argumented > that a high speed line is usually a main line. not a strong argument against usage=highspeed, a motorway is usually also a primary road and nobody complains. Imho this tag would be a good start. It says quite intuitively that the tracks are used (mainly) for high speed trains whatever that means locally. Actual speed limits and such can be mapped with existing separate tags. > The more vague a definition is, the more happy data consumers are if OSM > contributors do the classification. don't understand what you are saying here. > > Just to say that it is called "Hochgeschwindigkeitsstrekce" in German, > > or is there something more implied like special traffic rules, special > > signaling, freight train exclusion? > > Perhaps all this properties should be tagged in separately? > > Most of these properties are all tagged separately: > > - Train protection using railway:<system_name>=yes/no [yes, this scheme > is not a well designed tagging scheme] > - Speed limit using maxspeed=* and maxspeed:*=* > - Usage is difficult to tag and derive from OSM. There is > railway:traffic_mode=freight/passenger/mixed but one regular freight > train is enough to use "mixed". Types of passenger trains (local vs. > InterCity vs. high speed) are mapped as route relations but then you > have to parse and understand ref=* because service=* is not mapped on > all route relations. Germany has a handful of real high speed lines (>= > 250 kph) which are used by local trains, too. again, the definition can be country specific and the more precise meaning could be refined with special tags. In most countries highspeed routes are reserved for special highspeed trains but exceptions exist. Think of motorways, in Vancouver BC they have (or used to have?) a bicycle lane. Omg.. there is no rule without exception. > - Fences are mapped as you would map them. It is difficult and not > effient to determine if a railway line is fenced. In addition, mappers > in rural areas have more important things to map than fences along a > railway line in the middle of nowhere. Btw, older high speed lines in > Germany are not fenced at all. I consider fences pretty important - as a hiker I tend to cross single and double railway tracks wherever I like - with the exception of high speed lines which I consider from somewhat hazardous to nearly impossible to cross alive even under good conditions. This is in fact my definition of a highspeed line. > Some decisions could be automatised if OSM were finish and each object > had one dozen extra tags. But even roads usually lack information about > surface, width and lanes. even nastier, for any road without oneway=yes you can't be sure whether the tag is simply missing or its a known twoway road. To avoid such problems tags like usage=highspeed are somewhat better than highspeed=yes. Taken together I think usage=highspeed has a strong rationale and would be easy to understand and apply. What is missing is a simple way to tag the visual appearance of those concrete monsters of recently built dedicated highspeed lines. They are a landmark and obstacle with a strikingly distinct (even if locally different) appearance and technology. Would that be highspeed=yes? Richard _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
