I hate to say it mate, sorry but it has been mentioned before.
You need to completely uninstall TRS19, once a file has became corrupted that's it! Game over.
Make sure that you back up your user data before uninstalling, saves a lot of hassles trying to reinstall everything all over again
I would suggest using either WinRAR or WinZip
Then navigate to: C:\Users\%Username%\AppData\Local\N3V Games\TRS19 open the 'Build xxxxxxxxxxxx" folder
Select the following folders
Local
Original
Packages
Note: If you build routes, select the 'Backups' and 'Editing' folders. If there are NO files inside the Editing folder you don't need to back it up.
Optional: You can back up the screenshots folder, if you wish to keep your screenshots.
-----------
Uninstall TRS19 once you have completely done a full backup. Move the RAR file to Desktop so you can find it
Navigate back to C:\Users\%Username%\AppData\Local\N3V Games after TRS19 has been 'Uninstalled', click on the 'TRS19' select the TRS19 folder.
Hold Shift then press the Delete key, choose Yes to confirm.. This will delete everything corrupted within the 'User data folder'.
Now navigate to where TRS19 installation is 'Program Files' or 'Program Files (x86)'. Find a folder that relates to 'TRS19' or 'N3V Games'. As I have the Steam version, I have no idea what the default installation folder is called.
If you have TRS19 on Steam, navigate to C:\Program Files (x86)\Steam\steamapps\common then select 'Trainz Railroad Simulator 2019' folder
Again, using Shift + Delete key. Then click Ok to confirm!
Restart your computer
----------
Re-download the TRS19 'ONLINE' installer. Follow the prompts, when you launch TRS19, skip the configurator.
Sign into Trainz using your Trainz Account, then EXIT Trainz.
Using the RAR file, that you have backed up your Trainz content into.
Select the following folders inside the RAR file.
Local
Original
Packages
Not recommended, to select Backups or Editing..
Editing folder only if there are files inside this folder...
Extract to C:\Users\%Username%\AppData\Local\N3V Games\TRS19 inside the Build xxxxxxxxxxxx folder, choose yes to override if required...
Launch Trainz
Now, don't go ahead and click Start Trainz. LOL

We're not done yet!!!

Click 'Developer', then choose 'Rebuild Database'..
Once you have rebuilt Trainz database, this will restore all your payware DLCs and everything you have downloaded from the DLS.
But, do keep in mind that maybe only a hand full of items may need to be re-downloaded via Content Manager on the DLS.
----------------
Lets hope this solves your issues