Is this something that has just recently started or has it always been an issue with TRS19 (or earlier versions)?
There are a few things that could possibly cause this. Some may be caused by Trainz itself, others may be caused by Windows or your hardware (e.g. the GPU).
To go through a few of the possibilities:-
Check that your video drivers are up to date.
Are you running any software apps in the background that might be taking resources away from your system?
Have you created a route that is using a lot of assets with very high poly counts? This can severely reduce your frame rate particularly since you have a "lower end" GPU (the GTX 650) that may not be able to handle the load.
The image you posted is completely unreadable to me so I cannot see what your settings are. If you have any setting on "Ultra" then change them to "High". Likewise any on "High" change to "Normal" to see if that make a difference.