That statement is a bit vague.
What exactly is stopping you from adding locos and rolling stock? Do they not appear in the asset selection list? Are they coloured red in the list meaning "faulty"? Are they showing as faulty (e.g. missing dependencies) in Content Manager?
Lastly your post is in the Trainz Railroad Simulator 2022 thread but which version? Is it TRS22PE, TRS22 or Trainz Plus?
