Your are right there is an S class parked in Brunswick full time and pulls the train either north or south depending on the trains destination. The incoming locomotive then becomes the shunting loco until the next train, returning to Brunswick. The crews stay with their loco so the task of waiting is shared by all drivers. The PA class seems to have been parked in Picton and is not running. I have not spotted a DB class yet on mainline trains. There is a decent grade on the north east leg of the junction for eastbound trains, as well as a grade on the south east for south bound trains. I wonder if this has something to do with the exclusion of the PA class, having never gone up the hill. The shunting activites add about an extra 20 minutes to the trip each way.
The Australind is still running, although passengers are seated reverse for the Brunswick-Picton section. The Australind is also stopping on the branchline at the station crosswalk to let passengers disembark. It appears the line closure extends to the crossover near Beela road, excluding the mainline and station platform from use in Brunswick.
The old bridge was out on the 27th, I think but am not sure that the new one is in today, but will check.