We have other things to do besides searching for missing content.
Seriously, if you want to help yourself with missing assets, I highly recommend signing up for the Trainz Kuid Index.
Search assets by kuid (trainzkuidindex.com)
This is not free but it's inexpensive. It costs something like $10 or $15 a year and it's worth it, besides you'll find sites with all kinds of goodies in the process.