The two versions, TANE and TRS19 (all sub versions), are completely separate installs. They have have separate user data folders so as long as you do not delete the TANE install and its user data folder you will not lose any work previously saved in TANE. The TRS19 install will not be able to access your TANE work unless you first save your TANE routes and sessions as .cdp files.
In TANE CM select the routes/sessions either individually or as a group (this could be a huge file if you use this option), and right mouse click to use the "Export to cdp" command.
Then in TRS19 CM use the "Import content files" in the File menu to import them into TRS19. There will undoubtedly be some missing or unknown assets. Some of these at least will be in a DLC package.
From the TRS19 Launcher open the Content Store, type TANE in the text box near the top and scroll down to locate "Additional TANE assets for TRS19" and install.