ATS - Cummins ISX15 Sound V1.0

This simple mod replaces the sounds of Cummins engines on all SCS trucks with the sound of International 9900i.
Also adds a Cummins engine for Mack Anthem according to the brochure.

In my opinion, the Cummins sound from the 9900i is one of the best from the SCS today.

Authors: Sherman