Interesting how the tests are include one for the very factor I suggest might be a problem.
If there was no doubt that the 3000s could make the grade there would be no reason for testing.
What are they going to do if a test is failed?
What will they do if the ride quality is unacceptable?
Are they going to wet the track and add in a few leaves or some grease?
That said, testing is smart to give operators a way of best negotiating the underpass. I can see drivers being faced with the temptation to use it as a roller coaster.
Are they going to load the test car with sand bags to simulate passenger mass. (Will sand be dense enough to simulate Adelaide passengers?)
Unless they go out to Tonsley Junction or Oaklands they will have to work bang road on at least part of the journey.