Main sequence evolutionary tracks of single star models computed with basic network (blue triangles) and STERN network (yellow triangles) on the spectroscopic Hertzsprung-Russel diagram. Along each track, data points are separated by a time interval of 0.1 Myr. The black dashed lines show the boundaries of a region that is densely populated by Galactic stars, and the purple dashed line corresponds to the terminal age main sequence (terminal-age main sequence) line of the Galactic models of Brott et al. (2011a) (see fig. 1 in Castro et al. (2014)).