Range Tracks - SaneDevelopment/WPF-Controls GitHub Wiki
NumericRangeTrack and DateTimeRangeTrack are control primitives similar to System.Windows.Controls.Primitives.Track, but have three thumbs instead of one.
The Framework's Track scheme looks like this:

NumericRangeTrack's scheme is:
/images/NumericRangeTrackScheme.png
Uses as a control template for SimpleNumericRangeSlider and ZoomBar.
Remarks
The code for NumericRangeTrack was initially based on source code of System.Windows.Controls.Primitives.Track, extracted from PresentationFramework.dll (thanks to the Reflector). Original code was analized and enhanced for the purposes of range track.
DateTimeRangeTrack
DateTimeRangeTrack is a control primitive absolutely similar to NumericRangeTrack, but has System.DateTime values of some properties (such as Minimum, Maximum, StartValue, EndValue and so on) instead of double values.
Uses as a control template for SimpleDateTimeRangeSlider.