The only thing I can think of is there's something corrupted. You can try reinstalling the program from My Trainz and update with a new patch. Let the program build its own fresh database and test. If everything works, then connect to your own data. The program will then run a DBR and update everything and hopefully everything works.
If this doesn't work, put in a query to the helpdesk.
About eight months ago after a build update things were not working as expected. For a while a thought the new build was at fault. I decided to install a fresh copy of Trainz. I used the steps as outlined in post #32 by John. That resolved all the issues. Sometimes during an update the program does become corrupted leading one to believe that the update was bad.