Sandpatch Grade Substitution Fix

This mod fixes the overly broad substitution requirements on Sandpatch, fixing weirdness such as the Training Center SD40-2 showing up on trains, and the significantly out-of-era ATSF C40-8W and SD40-2 showing up as well.

I also included an optional fix to stop the New Journeys SD40 from substituting on Sandpatch, as that can substitute in place of the regular SD40-2 on occasion.