Class name:
 G4MeanFreePath

 Documentation:
 Keeps information which is related to the current
 status of the particle.


 Class name:
 G4MeanFreePathVector

 Documentation:
 Container class for G4MeanFreePath.


 Class name:
 G4SteppingManager

 Documentation:
 The manager to propagate the particle by one step.


 Class name:
 G4Track

 Documentation:
 A global object to keeps particle related information
 which is necessary to transport the particle. 


 Class name:
 G4TrackingManager

 Documentation:
 The manager to transport a paritcle from its birth to
 death. 


 Class name:
 G4Trajectory

 Documentation:
 Keeps the history of the trajectory of a particle. The
 trajectory is represented by a set of G4TrajectoryPoint object.


 Class name:
 G4TrajectoryPoint

 Documentation:
 Keeps information related to kinematics of a particle
 in one step. 


 Class name:
 G4UserSteppingAction

 Documentation:
 Utility class which keeps user interventions at the
 beginning and end of the one step of the transportation. 


 Class name:
 G4UserTrackingAction

 Documentation:
 Utility class which has user interventions at the
 beginning and end of the transportation.