For me I only use S20 for my routes (I can't stand the derp fest that is S10). What I have found is FPS issues generally come from high polygon assets (some are over 10,000), too many PBR textures can wreck havoc on FPS as well. Many asset creators build what they want to see, but never think about those folks on potato computers (like I have). A lot of assets don't have LODs (level of detail) which means they will always render no matter how far away you are from the object. Last year I bought the Fall Harvest Nebraska DLC, and man does it lag my system at the Bailey Yard (2 FPS going into that region) and it needs a massive update to 2025/26 standards). Billboard trees, and the older Speed Trees can cause FPS to drop to a snails crawl.
Trainz 22 has had issues since launch and that's based on many of the players here. Many will say lower your graphic settings, but that creates more visual problems than it's worth. Yeah for some it can break the immersion.
JCitron has stated multiple times on here that Trainz hits the read/write cycles of SSDs (or HDDs) harder than it really should which can ultimately damage the device. It can even cook GPUs. Trainz 22 runs excessively hot which will cause massive FPS spikes and also might cause damage due to the heat generated. Heat and circuits do NOT reaact well.
What I suggest is find the location that has the highest FPS impact, and examine every asset in that area. Look at polygon count, if it has LODs, and if you can swap those assets out for ones with reasonable versions (if available).
As a side note. When I ditched Windows 10 and moved to Linux Mint, for me Trainz performs a heck of a lot better. Why? Windows is the biggest resourse hog out there. That is something else few ever talk about.
