I have tried reducing all performance ratings to the minimum, but this mad the game no smoother.
I have deleted all but two consists, since I normally run this solely under AI with 40 trains running. Again, it made no difference.
I then ran a session of “Cornish Mainline and Branches” – perfectly smooth – as was a minimal route session I created from scratch.
So far, then, it seems to me that my layout has too much detail in it, although the “Cornish Mainline” is, I think, more detailed, or, and most likely, my layout is crap.
The Cornish Mainline has a lot of splines and lots of other close detail objects that bog things down a lot. There's something to try though that I think might work.
Within the settings in TRS2019 its self, not at the Launcher under performance, is the settings for tree details and draw distance, etc.
Either at the main menu, where the big selection buttons are for Driver / Surveyor, My Collection, etc., or within your route, click on the very top of your screen in the left corner. The 3-bars will show up.
Click on the 3-bars
Click on settings
Click on Video Settings.
Ensure Process Objects Behind Camera is checked
Set your draw distance to about 6000m, or 8000m
Change your Scenery Detail to High
Tree Detail to High
Post Processing to High
These are the same settings I use and I found this really, really helps with performance. They're not at the highest, although that's possible with open routes, or if there are mountains, but for routes such as the Cornish Mainline with lots of close up details it's not worth the effort work for video card to do because there's so much detail going on it's pushing your video card constantly causing lugging and stutters.
If you know how to get to the menu already, don't take offense to me putting the steps here. This is to help others who search for the same information.