O-Bahn Busway - WikiHQ

The O-Bahn Busway is a guided busway that is part of the bus rapid transit system servicing the northeastern suburbs of Adelaide, South Australia. The O-Bahn system was conceived by Daimler-Benz to enable buses to avoid traffic congestion by sharing tram tunnels in the German city of Essen.

Adelaide's O-Bahn was introduced in 1986 to service the city's rapidly expanding north-eastern suburbs, replacing an earlier plan for a tramway extension. The O-Bahn provides specially built track, combining elements of both bus and rail systems. The track is long and includes three interchanges at Klemzig, Paradise and Tea Tree Plaza. Interchanges allow buses to enter and exit the busway and to continue on suburban routes, avoiding the need for passengers to transfer to another bus to continue their journey. Buses can travel at a maximum speed of , but have been restricted to a speed limit since 2016. , the busway carried approximately 31,000 people per weekday.

The development of the O-Bahn busway led to the development of the Torrens Linear Park from a run-down urban drain into an attractive public open space. It has also triggered urban development around the north-eastern terminus at Modbury.

Track

thumb|A section of track used for testing O-Bahn buses|alt=A short section of the O-Bahn Busway

The O-Bahn track is made of concrete; it is elevated from the ground because of the poor quality of alluvial soils along the River Torrens, which frequently move due to their high level of plasticity. On top of the pylons are concrete sleepers on which the track rests. 5,600 pylons were drilled in place to support 5,600 sleepers and 4,200 prefabricated L-shaped track pieces, sited at intervals. The O-Bahn's concrete tracks were narrower and lighter than those of the initially proposed light rail development, and put less stress on the land. The concrete components were precast and then laid onto piers. On some sections was achieved in tests. The average service speed including stops is about . On entering interchanges the O-Bahn ends and the speed limit is . In the interchange area, the speed limit is . These were modified for O-Bahn use by Mitsubishi Motors' Clovelly Park plant before being bodied by Pressed Metal Corporation South Australia. The cost was included in the original $98 million budget. Modified MAN SG280s and SL202s were later purchased.

With the Mercedes-Benz O305s approaching their 25-year age limit, tenders were called in 2007 for replacements. The new buses were Scania K230UB rigid and Scania K320UA articulated buses bodied by Custom Coaches. , these, along with rigid Scania K280UB/K320UB buses, articulated Scania K360UA buses, one diesel/electric hybrid Scania K320UB, and one Mercedes-Benz O405NH make up the fleet.

In the case of breakdowns, a specially designed vehicle nicknamed 'Dumbo' is used to tow buses from the O-Bahn. In the early stages of design it was intended that all buses would have towing ability; however, this was soundly rejected by the drivers' union and 'Dumbo' was purchased. If a tyre blows during a trip the guide-wheel prevents the bus from erratic movement, and a smaller aluminium inner tyre allows the bus to be driven to the nearest station at .

Interchanges

thumb|[[Tea Tree Plaza Interchange|alt=View of a bus interchange from a bridge]]

Klemzig Interchange is the first station, from the city centre in the suburb of Klemzig. It was built as a connector to the city loop 'Circle Line' bus service, which followed the Adelaide outer ring route. Many bus services bypass Klemzig and the station has limited capacity. It contains a park & ride carpark with 450 spaces.

Tea Tree Plaza Interchange is the terminus, from the city centre, in Modbury. Adjacent to the Westfield Tea Tree Plaza, it is the largest O-Bahn station. Bus services from this interchange connect to areas as far away as Elizabeth and service the Golden Grove area. It has 700 car parking spaces, after a multiple level carpark was built during a redevelopment in 2013.

Route

thumb|alt=Map of the O-Bahn Busway

thumb|O-Bahn's southern entrance on Hackney Road|alt=A road entering a tunnel with signs indicating the tunnel is for buses only

thumb|Klemzig Interchange, one of the O-Bahn's two intermediary interchanges|alt=Bus interchange viewed from ground level

Outbound O-Bahn bus routes travel through the Adelaide city centre along Grenfell Street, and enter the O-Bahn via the tunnel (opened on 10 December 2017) through the Adelaide Park Lands in Rymill Park. They then exit the tunnel on Hackney Road, north of the intersection with Dequetteville Terrace, and then proceed northwards along the road in designated bus lanes. Along this stretch the Adelaide Botanic Garden is on the left, followed by Botanic Park. Hackney Road—along with the designated O-Bahn bus lanes—crosses a bridge over the River Torrens, with the bus lanes veering easterly, to the northbound entrance of the guided O-Bahn busway. The busway dips below the surface road (Park Road) to join the inbound (southbound) track, both heading northeast.

The busway follows roughly the Torrens River valley, but with smoother curves. This means that it crosses the river quite often, with either a park or a few houses on a point surrounded by the river and busway. This occurs a total of eight times before the busway reaches Klemzig Interchange on the north side of the river. The busway crosses the river again soon after Klemzig and passes Lochiel Park and part of the suburbs of Campbelltown and Paradise to its north between the busway and the river before reaching Paradise Interchange.

After Paradise Interchange, the busway passes under Darley Road, then over the Torrens for the last time. The terrain becomes steeper as the busway proceeds up along the outflow creek and past the northwestern side of the Hope Valley Reservoir. It proceeds north under Grand Junction Road, then swings east and north again to enter the eastern side of the Westfield Tea Tree Plaza shopping centre precinct, where the guided busway ends at Tea Tree Plaza Interchange. Most buses continue on normal roads to service suburbs further afield.

All listed routes connect Adelaide City Centre to the named endpoint, but service different suburbs between the O-Bahn interchange and that endpoint.

History

Planning

right|thumb|Track schematic diagram|alt=A schematic showing a top-down view, a front view and a 3D view of the O-Bahn Busway.

The greater Adelaide area experienced significant growth during and after World War II. Between 1944 and 1965, the area's population doubled, and the number of private motor vehicle registrations increased 43-fold. In 1955, the state government under Premier Sir Thomas Playford established a Town Planning Committee and commissioned a coordinated plan to guide the future development of Adelaide. The resulting 300-page study, "Report on the Metropolitan Area of Adelaide 1962", laid out a 30-year development plan, including a proposed of improved roadways. Shortly before leaving office in 1965, Playford commissioned a detailed study focusing on the recommended transportation improvements.

In 1968, the government received the Metropolitan Adelaide Transport Study (MATS) that envisaged a network of 10 freeways crossing the metropolitan area, a rapid rail network, and an underground city loop railway. MATS drew massive public opposition, as it called for the acquisition of thousands of properties and would effectively supplant a number of suburbs that were to become the sites of interchanges. Arguments broke out in Parliament, and widespread images of gridlock in overseas freeway networks contributed to the furore. Nonetheless, in early 1969 Premier Steele Hall approved implementation of the plan in a modified format, and the government began to purchase property along the proposed corridors. In mid-1969, faced with ongoing opposition, the state abandoned plans for 2 of the 10 proposed freeways. Hall was voted out of office in 1970, and the new government under Premier Don Dunstan passed a 10-year moratorium on freeway development, effectively shelving MATS. The already-acquired corridors were retained for potential future use.

By the mid-1970s, transportation had become a problem in the north-east suburbs. The population of the Tea Tree Gully region had increased from 2,500 in 1954 to 35,000 by 1971. A corridor of land along the River Torrens from Adelaide to Modbury, originally purchased for the Modbury Freeway proposed under the MATS plan, was the subject of a new proposal in 1973 when the State Director-General of Transport suggested building a heavy rail line that would connect the suburb to the Adelaide railway system. A subsequent study, the "North East Adelaide Public Transport Review" (NEAPTR), considered heavy rail, light rail, busways, and freeways, ultimately concluding that a light rail line or busway would be most viable. The state government decided on a light rail proposal to extend the historic Glenelg tram line. The new route was to continue along King William Street beyond what was then the terminus in Victoria Square and weave through the Adelaide Park Lands to the Modbury corridor. The light rail system would connect with feeder buses at stations along the length of the corridor to transfer passengers to suburban routes. New light rail vehicles were to be bought to replace the ageing 1929 H type trams. the O-Bahn system was developed for use in tram tunnels in Essen. After extensive consultations with German authorities, State Transport Authority engineers decided the O-Bahn could be used. The system was seen as far superior to previous proposals; it used less land, made less noise, was faster and cost less. In addition, its unique feature of a non-transfer service direct from suburban streets to the city centre made it more attractive. Plans were drawn up for a length of : initially only were to be constructed as O-Bahn, with the rest being conventional busway. However, safety concerns and public opposition led to O-Bahn being used for the entire length. Construction began in 1983 for the first section to Paradise Interchange. Another change of Government in 1982 resulted in uncertainty over the future of the project. The John Bannon Government, after consultations, decided to continue with Stage 1 (City to Paradise) and in 1986 proceeded with Stage 2 (Paradise to Tea Tree Plaza). The cost of the project was $98 million, including the buses.

Stage 1 opened on 9 March 1986. Stage 2 opened on 20 August 1989.

The O-Bahn had more than 4 million passenger trips in the year after completion of Stage 1 in 1986, with a 30% increase the following year.

A southern O-Bahn proposal attracted the most attention and has been the subject of various studies and Parliamentary Committees as to its viability since 1996. The rail route through Adelaide's far south is off-centre, without the large catchment area of a more central transport route. An O-Bahn running direct through the region would be able to take advantage of an already large population and the continuing growth in the area. The O-Bahn would end there, with buses continuing on the Southern Expressway through the far south. Construction of this O-Bahn would require moving the railway track slightly to fit the O-Bahn alongside. In addition, Emerson Crossing and the Goodwood Overpass would require alteration. The estimated cost of construction, $182 million, was considered too expensive, and the proposal was suspended in 2001. Since then, the Government has focused on upgrading South Road and extending the Glenelg tram line.

There was a 2009 plan that bus routes serving the O-Bahn would be enhanced from Hackney Road along Grenfell and Currie Streets and extended to West Terrace on the far side of the CBD along dedicated bus lanes. However, the Federal Government announced in January 2011, as part of its response to the 2010–11 Queensland floods, that the extension would be cancelled "as a result of a significant scope reduction of the original project, resulting in only limited transport benefits".

O-Bahn City Access Project

thumb|Entrance to the City Access project tunnel at Grenfell Street

In 2015, the Department of Planning, Transport & Infrastructure announced a $160 million proposed O-Bahn City Access Project. The existing entry/exit at Hackney Road was retained, but upgraded bus-only lanes on Hackney Road now lead to a new tunnel portal with bus guide rails commencing near the Adelaide Botanic Garden. The tunnel passes under the Botanic Road intersection, then curves west under Rundle Park / Kadlitpina, Rundle Street and surfaces in Rymill Park leading to a redesigned intersection at Grenfell Street and East Terrace. Construction started in late 2015 and completed in 2017. The contract to complete the detailed design and construct the tunnel was let to McConnell Dowell in October 2015. Sage Automation provided expertise in the mechanical and electrical aspects of the tunnel including ventilation and safety systems. Construction started in March 2016 with the removal of the median strip and preparation of central bus lanes. The tunnel opened on 10 December 2017, with limited services starting the next day. It started full operation on 17 December.

Effects on local development

The O-Bahn has caused a clustering of commercial and community development near the Tea Tree Plaza Interchange, as service-providing organisations and businesses have sought to exploit the area's easy accessibility to public transport and the city centre. Market imperatives have also been aided by the zoning of the land around the area as commercial rather than residential. In contrast, there has been opposition to the area surrounding Klemzig Interchange and Paradise Interchange being used for any purpose other than low-density housing and no transit-oriented development has occurred.

Environment

thumb|Linear Park near [[Paradise Interchange|alt=A grassy park with trees in the background]]

The construction of the O-Bahn, rather than the previously proposed Modbury Freeway, was motivated by a desire to reduce car dependency. $6 million  was used for the redevelopment of the Torrens Gorge, in which the Torrens Linear Park was created. About 150,000 trees, plants and shrubs were planted alongside the track for aesthetic, environmental and noise-reduction purposes; planting was completed in 1997. Torrens Linear Park rejuvenated the river, which had deteriorated to the extent of being a de facto "urban drain, littered with rubbish and inaccessible to the public". Arising from environmental considerations, the O-Bahn is carbon-neutral due to the absorption of carbon dioxide by the trees alongside it. The design of the O-Bahn allows for the installation of overhead wires for trolleybuses.