| Re: "stop post" / "platform edge" reference from ocpTT (was: stop probability) [message #856 is a reply to message #845] |
Thu, 08 November 2012 21:31   |
Dirk Bräuer
Messages: 311
Registered: August 2008
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Senior Member |
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Dear Susanne and Joachim,
> * The <ocpTT> may already refer to the appropriate <track> where the
> <platformEdges> and <stopPosts> may be defined.
+1
> * The <stopPost> itself may refer to a certain <platformEdge>.
+1
> * A reference from the <ocpTT> to either a certain <stopPost> or a
> certain <platformEdge> is currently missing.
But they would be a kind of redundant to "the way via the track" which you
described above.
The 'platformEdgeRef' alone would not be redundant for the very special
case if there are two platform edges at the same track and the train is
scheduled to open the doors at one of them only...
I do not know this case from practice. So, I think we should wait until it
happens, if ever...
> Both attributes are needed for different modeling levels. Some
> software tool handles platforms without stop posts another tool
> may only accept stop posts but no platforms.
In other cases of that kind, RailML forces the user to use the one and
only way "in a wider sense". For instance, we force to create OCPs to
describe a timetable even for programmes which do not handle OCPs
(stations) themselves. We force to create <trainParts> to describe
arrival/departure times even for programmes which do not handle parts of
trains. I could name much more examples of that kind.
So why not "forcing" to use <ocpTT>.trackRef to come from a train to
platformEdges and stopPosts?
To reduce redundancy, I would prefer this way. I totally agree with
Andreas Tanners arguments on redundancy in an earlier. Andreas, now we can
avoid new redundancy here, I hope you also plead so.
> * The current 'trackInfo' attribute in <ocpTT> would be marked
> deprecated.
Generally: I understand and tend to agree. But: Do we possibly need the
"trackInfo" for additional (plain-text) info on the stop? Possibly remarks
for the passengers to be printed by a passenger information system?
Possibly for the difference between the railway-internal (IM's) track
number and a published platform number (think about Czech platforms -
there is a platform name additionally to the track number).
For the moment, I would leave the 'trackInfo' for individual plain-text
use like "remarks".
> Is there the need for more than one reference to either a 'platformEdge'
> or a 'stopPost'?
I don't think so. I would provide only one way and wait until somebody
claims and explains why there is a need for another one which is not
redundant.
Best regards,
Dirk.
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