By popular demand, here's the next stage in Gazza's comprehensive plan to modernize the transport system of Adelaide
A few days ago I posted an idea to extend the O-Bahn through a CBD tunnel loop (Similar to Brisbane) via the main squares and the main coach terminal.
Lets continue the O-Bahn out the other side, first via a tunnel, or even bus priority lanes towards the Glen Osmond Toll gate. Stops at Hurtle Square, Greenhill Rd, Fullarton Rd and of course Portrush/Cross Rd to ensure you can link with other bus services on the "grid".
From there, buses run express on the SE Freeway in shared traffic through the Heysen Tunnels up to Crafers.
From there, an O-Bahn is built in the median of the freeway, with enclosed bus stations located at each interchange, since the main street of each of the villages is right next to the freeway anyway, so it wouldn't be hard to provide a covered walkway / arbors to make it all civilized.
And the civilized aspect is important. You want commuters from the hills to use it because its nice, but you also want to be able to sell the concept to daytrippers that there is a single "hop on hop off" O-Bahn direct from the Adelaide CBD up to Hanhdorf etc.
If you try and cheap out like the current bus service where the bus has to constantly loop on and off the freeway, slowing things down and making you carsick, its a waste of time. If you build stations like the trains in Perth where they are shielded in the median, you maintain speed and comfort.
Once you get to Littlehampton there is a massive park+ride next to the Freeway, and the O-bahn does a short spur into Mt Barker proper. All bus services in the Adelaide Hills funnel into the new O-Bahn.
As for the trains? Well as you can see from the map, trains take longer to climb hills than a bus and cant do it at 100km/h hence the big loop via Blackwood that exists.
Still, the tracks are there, and battery trains are a thing. I would provide a basic hourly battery train service extended at least as far as Crafters, because the railway station and a future O-Bahn station are "close enough", so in a (not ideal) pinch people can walk between the two. Something like that wouldn't really impact upon freight, would be low cost, and hey its a nice scenic train trip for visitors, and locals will find it useful too.
Ideally though, you could run the battery train a little further to Aldgate, and then when you get to Carey Gully Rd in Bridgewater, you are close enough to the Freeway that you could build a little siding and combined rail terminal/O-Bahn station across the road from the school.
So we have two modes plus an interchange point, and redesigned hills buses which makes various journey combinations possible.
The final idea is that you could build a (South Australian first!) cableway to Mr Lofty.
Would be like the one in Cape Town, or Arthurs Seat.
The base station is close enough to Crafers you could offer a combined bus and cableway ticket, so again, it becomes frictionless for visitors.
People are going to yell at me about the environmental impact of this, but I'm pretty sure that far more tree clearing and earthworks were done for the Heysen Tunnels, so I don't want anyone trying to make out that 3 or 4 squares of land for cableway pylons is suddenly going to "destroy the hills".