They have to get a fair few hours up before they'll be rolled out (and I don't believe a date has been announced for the rollout yet). But you can expect to start seeing them test a long the werribee, Frankston, craigieburn, and upfield lines sometime soon! They're also apparently planned to run along the racecourse line, so I wouldn't be surprised if they test a long there as well
Something I noticed from TaitSet's photos, is that they all have those "MADE IN VICTORIA FOR VICTORIA" stickers on every few windows, like vlocities do. I've always found that a bit obnoxious, I mean while it's testing it's probably fine, but they eat up half the window space