Thanks for installing this Amtrak California passenger car pack! the installation guide is listed bellow:

1. Drag-drop or copy-paste the extracted Assets folder

2. Copy BaggageCoach.GeoPcDx, & CoachInterior.GeoPcDx from:
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Surfliner\Baggage

3. Paste BaggageCoach.GeoPcDx, & CoachInterior.GeoPcDx to:
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Amtrak California\Baggage

4. Copy Business.GeoPcDx from:
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Surfliner\Business

5. Paste Business.GeoPcDx to:
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Amtrak California\Business

6. Copy CafeCoach.GeoPcDx from:
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Surfliner\Cafe

7. Paste CafeCoach.GeoPcDx to:
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Amtrak California\Cafe

8. Copy CabCarCab.GeoPcDx from:
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Surfliner\Driving Trailer\Cabview

9. Paste CabCarCab.GeoPcDx to:
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Amtrak California\Driving Trailer\Cabview
&
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Amtrak California\Driving Trailer RF\Cabview

10. Copy CabCoach.GeoPcDx from: 
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Surfliner\Driving Trailer\Engine

11. Paste CabCoach.GeoPcDx to:
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Amtrak California\Driving Trailer\Engine
&
Railworks\Assets\RSC\PacificSurfliner\RailVehicles\Passenger\Amtrak California\Driving Trailer RF\Engine

you are done! enjoy!