What is the Obarn?
Lets start with why the O-Barn was built. In the late 20th century, our Northeastern suburbs were starting to experience heaps of population growth and these suburbs were meant for families but were car-dependent as they were far from any ‘decent’ public transport (i.e Rail and Trams (Buses aren’t the best)). As well as the rail only serving the north, south and western areas.
The large amounts people living in these areas lead to heavy use of buses but the commute into the city was getting slower and slower and even longer in peak traffic.
Road planners had to solve this dilemma:
- Congestion was getting worse.
- Demand for a faster route into the city was rising.
- The existing roads couldn’t cope.
- Rail couldn’t be done due to cost and land issues.
Why didn’t they build a train line?
The public thought that just building a train line (Could of been called something like the Paradise or TTP line) would make the most sense but many studies in the 1970s and early 80s showed major problems:
- High Costs of building new tracks and stations. As well as buying back land for the use.
- The proposed rail would have less flexibility (Could not serve suburban streets, like a bus or tram).
- Rail infrastructure is fixed so you can’t change it when needed for detours or crashes.
- Just building a train line would duplicate the current bus coverage without improving coverage.
So the government when back to the drawing board and found this…
The O-Barn concept
The SA transit officals looked at Europe, and particularly Germany where guided busways were being used in some places including Essen. With these systems using a concrete guided track with buses being retrofitted with little guidance wheels on the side to allow the buses to travel at high speeds without drivers needing to steer. Way after this, many places also now have guided busways like in Cambridge.
Parker, D. (2019) Guided bus derails in Cambridge, New Civil Engineer. Available at: https://www.newcivilengineer.com/latest/guided-bus-derails-in-cambridge-24-02-2016/ (Accessed: 14 June 2025).
This concept had massive appeal as it:
- Allowed for high-speed and congestion-free running
- Could use existing bus fleets (Just a little change needed)
- Buses could leave the busway at any interchange to run regular services
- Cheaper then a railway
- Avoided major land acquisitions and tunneling
The Politics
The proposal was heavily supported by the premier at the time (Premier John Bannon), who saw the O-Barn as forward thinking and a cost-effective alternative to traditional rail while still acting like it.
The O-Barn ticked of all of the governments goals which where to:
- Modernise Adelaide’s public transit
- Keep infrastructure pricing under control
- Support the rapidly growing northeast suburbs
- To be a show off and to show how SA is a transport innovator.
Construction on the O-Barn began in 1983 and Stage 1 was opened in 1986 from Hackney Road to Paradise Interchange with the later extension to Tee Tree Plaza (Modbury) in 1989.