class GTrackChunk : public edm::AbsChunk {

.
.
.
                                                              ----- words per -------
private:  // persistent attributes -- these must be mutable   event  track state  fit

  // Version indicating format of persistent data.
  // Used for schema evolution.
  mutable int _version;                                            1

  // Identifier lableling the type of tracks in the chunk (CFT,
  // CFT+SMT, w/ or w/o m.s., etc.).
  // Default is 0.
  mutable int _content_id;                                         1

  // Version of the cluster pointer indexer
  mutable int _cluster_indexer_version;                            1

  // List of parent chunks.
  mutable ChunkList _parent_chunks;                               few

  // List of cluster chunks used directly or used by ancestor
  // Gtrack chunks.
  mutable ChunkList _cluster_chunks;                              few

  // Number of states in each global track.
  mutable StateCountList _state_counts;                                 1

  // S for each state.
  mutable SList _ss;                                                         1

  // ETrack lists.
  mutable SurfIndexList _surf_indices;                                            1
  mutable SurfaceRecorder _surfs;                                 few
  mutable ETrackParamList _etrack_params;                                        20

  // Surface direction list.
  mutable ForwardList _forwards;                                                  1

  // Fit status list.
  mutable FitStatusList _fit_statii;                                         1

  // Cluster pointer list.
  mutable ClusterList _clusters;                                             1

  // Chi-square list.
  mutable ChiSquareList _chi_squares;                                             1


Total words/track assuming 20 clusters/track and 2 fits/track         1  +  60 + 46
This may be a mixture of 32 and 64-bit words.                       = 107 word/track