For this soundset, Pacific Surfliner is required. JDTS's Amcal Repaints are suggested. Install instructions are below the button, and please DON'T REDISTRIBUTE! (All credit to rightful owners of videos from which I got the sounds.)
Features:
Enhanced Horn and Bell sounds.
Separate Interior and Exterior sounds.
STEP 1: Download attached file above.
STEP 2: Unzip.
STEP 3: Drag "ZsTsMods" into Railworks/Assets.
STEP 4: Copy the PROXYXML from the 8300 series cabcar of your choice.
STEP 5: Paste into Assets/RSC/PacificSurfliner\Audio\RailVehicles\Passenger\CaliCar\Cab.