In this work, new empirical equation describing the charged particles radiation track development
against etching time and track longitudinal depth are presented. The equation involves four free fitting
parameters. It is shown that this equation can reproduce tracks depth formed on the CR-39 by alpha
particles at different energies and etching times. Parameters values obtained from experimental data can
be used to predict etched track lengths at different energies and etching times. The empirical equation
suggested is self consistent as far as reproducing all features of track depth development as a function of
etching time and energy are concerned.