Hi, sorry for the late response on the mailing list, I accidentially send the email only to Richard.
Am 11.07.2017 um 10:49 schrieb Richard: > without a proper definition there is no way to resolve your dispute > and the tag is unverifyable and of limitted use as is. 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. Fliefy uses highspeed=yes for tracks with at least 200 kph. I agree with that. But other mappers disagreed when we discussed that in real life the last time. That was three years ago. There is a plenty of examples of potential highspeed=yes on not-so-fast tracks: - The stations Fulda, Kassel-Wilhelmshöhe and Göttingen (all along high speed line Würzburg–Hannover). Speed limit is about 100 to 140 kph for trains passing these stations intentionally. - The tracks at most junctions of the old and new railway line from Karlsruhe to Basel are part of the new high speed line. Where the two lines separate, the speed limit is 100 kph because these junctions are of temporary nature and they did not want to spend much money for expensive high speed points. Once the whole line is finished (in about 10 to 20 years), they will be removed. Btw, the speed limit on the old line is 160 kph and 250 kph on the new line. - The high speed line Leipzig–Nuremberg runs through Erfurt Central Station on its own tracks but with a speed limit much below 160 kph (outside the station and its surrounding 300 kph). - The Northeast Corridor between Washington and Boston has sections where the train is "slow" (changeset discussion I linked in my initial posting). Should all those junctions and stations and the other parts of the line get highspeed=yes although they are not suitable for high speeds? If yes, this would open a new discussion where the line should begin and end. Its a decision which is difficult or impossible to research *on* *the ground*. I would like to avoid that. > 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. 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. The more vague a definition is, the more happy data consumers are if OSM contributors do the classification. > 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. - 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. - Even older railway lines might have nearly no level crossings any more (e.g. Karlsruhe–Basel has only four level crossings although it is not a high speed line). - You have to map all platforms to determine if a railway line does not pass platforms. 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. Best regards Michael -- Per E-Mail kommuniziere ich bevorzugt GPG-verschlüsselt. (Mailinglisten ausgenommen) I prefer GPG encryption of emails. (does not apply on mailing lists)
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