I am going to summarize the ATLAS tracking EDM classes for my own record.
The track object itself is not used in the analysis preparation nor in the analysis stages. Rather, it is the
TrackParticle 
, specifically designed to be light weight and to carries all the track information needed for analysis and maintain the link back to the original track behind the
TrackParticle.
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SiinnChe - 2015-02-27