At a minimum
, All of your
User Data folders. (Note that it is best to name these yourself with a descriptive name so that you know exactly what those folders represent. Don't accept program suggested auto-generated names like 'Build xyz4590' etc.)
I call mine 'UserData' and place that on my fastest SSD drive and point the program to that as the
'Local Data folder' in Trainz settings.
(Recommend getting it out of your C:\Users\[username]\AppData\local\N3V Games\ folder on C: Drive).
My program files are in C:\TRS2019 and the user data/ packages ones are in a sub-directory of that: i.e. in C:\TRS2019\UserData, since my boot drive is my fastest SSD, which also has ample space for both the Operating System, my program files and TRS19.
In general, however, I'd recommend COPYING all of the Trainz
Program folders AND the
Userdata folders to another HDD or external Drive to create a fairly bulletproof backup system.
Do this whenever you're about to patch a version or whenever you've made some significant changes to your routes and sessions.
If something goes wrong, then all you need to do is to copy the entire set of folders back to your usual drive to recover your work.