Find original copy of a charged track

For copies of charged tracks, the function KCHT returns the original track number in the CHT section.

KCHT (ITK)

If KFCHT $\leq$ ITK $\leq$ KLCHT, KCHT (ITK) is equal to ITK. Otherwise (i.e., ITK is a copy of a track in the CHT section), KCHT (ITK) equals the corresponding track number in the CHT section. This function can be used only for charged tracks; for other objects, use KSAME.