The sounds I have for it are:
<kuid2:45324:53008:1> required by CV GP9 black, CR GP9 patched PC(former PRR), PC GP9 late (former PRR), CNW GP7 Phase II and JRPX GP7
and <kuid2:37581:1184:3> required by CR GP9 patched PC(former PRR), EMDX SD80MAC, CR C40-8, PC GP9 late (former PRR), ITC GP7 Phase II, JRPX GP7, CNW SD80MAC, PRR GP9 early, MQJR S12 20, BNSF GP9#1629 and BNSF SW1500#3604
(with <kuid2:45324:54002:5> for the sound library).
All bought JR direct.