If you have Trainz Plus then you are, in reality, already running TRS22 "on steroids" with all the Plus only features added in. My timeline has both Plus and TRS22 but I do not (yet) feel the need to install TRS22 as a separate program so I am only running Plus.
I actually have two installs of Plus, one is set to the beta stream and the other to the "retail" or non-beta subscription stream.