TrackerNet
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TrackerNet
TrackerNet is an fixed-line diagram/information service, implemented between 2007 and 2009(?) that shows signals, points, and a history of all train movements derived from the ATP sensors.
It shows an approximation to a signalman's view for the entire network, but intended for management/quality control, not safety-critical information.
The originally SVG system UI is implemented as a C# WPF (XAML) application. The related Train Lists application provides predictions of arrival times, which the publicly available data is derived from.
Unfortunately, despite having up to 23,000 internal clients, performance was not considered a priority.
The TrackerNet original system was supplied by Roy Herbert, TrackerNet supplied point, signal and line information for the Bakerloo line in August 2005, using OPC to encapsulate the legacy LU systems this supplied xml to server (SQL Server 2000) which upon request would update SVG, This was achieved using javascript timeout(interval, func pointer) function, passing max of changes from the previous conversation with the data server, thus only fetching what is new in a recursive process the corresponding SVG elements are then updated if any state change has occurred. The original concept was jointly developed by Jeremy Stockbridge and Roy Herbert of Bryce Technologies; re Tri Controls (TrackerNet, Dalmure Scotland) extreme weather tracking system, the original LU pilot system was designed to supply max 1000 users, with updates every 0.3 of a second, and took 3 months to implement across the line. London Underground operates TrackerNet which allows staff to observe electronically the movement of rolling stock on the Tube network. It is presently being introduced for all London Underground lines and is in full operation on the Circle line.
API
The API service runs on IIS 7 ASP.NET 4.0.30319, with customErrors mode="off".
In June, a required feed for some of the data was being turned off every night at between 01:45 AM and 6 AM, but this was fixed after a couple of days.
There currently appear to be three or four servers mirroring the feed - this can be seen by the timestamps returned in the XML. This suggests is may be possible to track at higher resolution than 30 seconds.
Services
Documentation is at www.tfl.gov.uk/assets/downloads/businessandpartners/Trackernet_Data_Services_Guide_Beta_0_2.pdf. The original service's documentation was taken from data.london.gov.uk/documents/apibeta-trackernet-services-guide.pdf.
The API URL in the documentation is not accurate: it is actually cloud.tfl.gov.uk/TrackerNet/. The URLs are all case-insensitive.
There are currently four documented data services available from London Underground that will return cached information about train predictions and network status. There were also three more services that were undocumented, and now unknown. Usage of these is undefined and in certainly unsupported by TFL.
| Feed | Documentation | Works | Documented |
|---|---|---|---|
| 4 | Train predictions (summary) | Yes | Yes |
| 5 | Train predictions (detailed) | Yes | Yes |
| 6 | Station status | Yes | Yes |
| 7 | Line status | Yes | Yes |
Examples
See TrackerNet YQL notes
select LCID, LN, TrackCode, SetNo, Location, Destination from tfl.trains.detail
where line in ('B', 'C', 'D', 'H', 'J', 'M', 'N', 'P', 'V', 'W') and maxtime=1000 | unique(field="LCID")
More reading
channel9.msdn.com/shows/ARCast+with+Ron+Jacobs/ARCastnet-See-the-London-Underground-with-WPF/
www.uclic.ucl.ac.uk/distinction-projects/2008-webb.pdf
