This is a simple sound patch that requires a few payware and freeware addons to enhance your route sound experience. This mainly changes the horns on the SD35 and GP40-2 to Searchlight ones (K3LA and RS3L), the wagon sounds to Krellnut's, and the GP40-2 external engine sounds to Searchlight's EMD 645E3 sounds.
Searchlight CR Leslie RS3L:
Searchlight EMD 16N-710G3B Sound enhancement:
Searchlight EMD F40PH-2CAT CALTRAIN SOUND ENHANCEMENT PACK:
Searchlight EMD 16-645E3 SOUND ENHANCEMENT PACK:
Simply just drag and drop the "assets" folder located in the soundpatch folder to your Railworks directory and you are done!