To refit the Tracks add the following lines to you option file.
<code>
seq = GaudiSequencer("mySeq")
seq.Members += [TrackStateInitAlg("myInitAlg")]
TrackStateInitAlg("myInitAlg").TrackLocation = "Rec/Track/Best"
TrackStateInitAlg("myInitAlg").addTool( TrackStateInitTool("TrackStateInitTool" ) )

fitter = TrackEventFitter("myFit",TracksInContainer = "Rec/Track/Best")
fitter.addTool(TrackMasterFitter('Fitter'))
fitter.Fitter.addTool(MeasurementProvider('MeasProvider'))
fitter.Fitter.MeasProvider.IgnoreTT = False
seq.Members += [fitter]

### avoid crash by missing channels 
itClusterPosition = STOfflinePosition('ToolSvc.ITClusterPosition')
itClusterPosition.DetType = 'IT'
</code>