Today I found a way to use RW_Tools to make a list of all my collected rolling stock and Locomotives. I saved it as an Excel file and when putting together a consist this makes it easy to find a particular rail car by type or road name. This also separates by provider and makes it easy to select the proper asset in the editor. Just highlight the correct column and use Ctrl+F and it highlights all your choices. It listed over 6020 items. There is probably an easier way to do this but this works for me.
EDIT: changed the asset count.