Unlike most I have once caught the BWT to Tanunda for a Barossa experience. Having recently returned from touring overseas I found the service stacked up well against European and US counterparts. It was a success in the early 2000s but probably because it was not facing the high track access and regulatory charges that now apply. Track speeds were still acceptable and the Blue Bird ride excellent.
In 20 years of neglect rail tracks do not last; I was a foundation member of Pichi Richi and we found that out very quickly.
Any viable train run to the Barossa would require enormous amounts of money spent on the track. Then you have to find suitable vehicles which needs money to bring up the current regulatory standards; some of these are now quite draconian. Clapped out Red Hens are not likely to be popular with the tourist public.
Money would be better spent on both Steam Ranger and Pichi Richi, both of which have viable (near) operations and have proven tourism potential but are undercapitalised.
To restore commuter rail to the Barossa implies that Barossa residents want a rail service that will take them to the CBD or perhaps Elizabeth. I am willing to wager that most who might commute from the Barossa don't go to places served conveniently by rail. To make a commuter service viable there must be passengers, that means people living in the catchment area. To get passengers you must build houses, to build houses you must subdivide land, to subdivide land you must cut up vineyards. I now live in the Clare Valley so cynically I can support this, more tourists to Clare. We have a saying up here, "they promote the Barossa to keep the riff-raff out of Clare.
A three times a day train, as proposed above, is not a service acceptable to 21s century commuters used to the flexibility of their own vehicles.
The break of track at Krommer's Crossing does not stop a train running to Tanunda if it was ever viable; the track can be relaid through a roundabout if ever necessary.
As for the local member, I am sure he knows there are more votes in an improved road junction than in a clapped out rail system.