On www.trainzkuidindex.com you can try to search without the version (only 45324 and 6703). You will get the version 3 on jointed rail and on the DLS. Maybe it can works for you.
kuid2:45324:6703:1 = SD70MAC engine by norfolksouthern37. There is a updated version being kuid2:45324:6703:3. Should be able to get it from Jointed Rail.