The O-Bahn Busway (also known as the Northeast Busway) in the South Australian capital city of Adelaide is the world's longest and fastest guided busway. The O-Bahn — from the Latin omnibus ("for all people") and the German bahn ("way" or "road") — was conceived by Daimler-Benz to enable buses to avoid traffic congestion by sharing tram tunnels in the German city of Essen.[1] The route was introduced in 1986 to service Adelaide's rapidly expanding northeastern suburbs, replacing an earlier plan for a tramway extension.
The design is unique among public transport systems; busways typically use dedicated bus lanes or separate carriageways, but the O-Bahn runs on specially-built track, combining elements of both bus and rail systems. The track is 12 kilometres (7.5 mi) long and includes one station and two interchanges: Klemzig Station in Klemzig, Paradise Interchange in Campbelltown and Tea Tree Plaza Interchange in Tea Tree Gully. Interchanges allow buses to enter and exit the busway and to continue on suburban routes, avoiding the need for passengers to change. Buses travel at a maximum speed of 100 km/h (62 mph), and the busway is capable of carrying 18,000 passengers an hour from the Central Business District to Tea Tree Plaza in 15 minutes. Services are operated by Torrens Transit under contract from Adelaide Metro, an agency of the South Australian Department for Transport, Energy and Infrastructure.
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Adelaide has had significant population growth since the industrial expansion following World War II, with the population having tripled from 321,400 in 1938 to 1,129,269 in 2005.[2][3] Concurrent with this growth, a transport blueprint, developed with American assistance, was presented in 1968: the Metropolitan Adelaide Transport Study (MATS). The plan envisaged a large network of freeways crossing the metropolitan area, together with an underground city loop railway. One of the freeways to be constructed was the Modbury Freeway, connecting a city bypass route with the then predominantly barren and undeveloped north-eastern suburbs. The freeway was to be built in a linear park alongside the River Torrens.[4][5]
The size of the MATS plan resulted in considerable public opposition; several suburbs were to completely disappear under interchanges, with Hindmarsh to be removed to make way for a multi-entry interchange. Widespread images of gridlock in similar overseas freeway networks also contributed to this opposition. The plan was abandoned by successive governments, and much of the land held by the Highways Department was sold off for housing developments. However, the land for the Modbury Freeway was retained and later renamed from "Modbury Freeway Corridor" to "Modbury Transport Corridor". The Modbury corridor was left to degrade, eventually becoming landfill.[5][6][7]
The population of the Tea Tree Gully region increased from 2,561 in 1954 to 91,921 in 2001, through new housing developments. In 1973, the State Director-General of Transport spoke about using the Modbury corridor for public transport to improve services in the area, initially suggesting a heavy rail line be constructed to connect with the railway system. Over the next four years, the Department conducted the North East Public Transport Review (NEAPTR), which considered heavy rail, light rail, busways and freeways as options for the corridor. The study concluded in 1978 that a light rail line or busway were most viable. The governing Australian Labor Party, under Premier Don Dunstan, decided on a light rail proposal to extend the historic Glenelg tram. The new route was to continue along King William Street beyond the present terminus in Victoria Square and weave through the Adelaide Park Lands to the Modbury corridor.[6][9]
The light rail system was to connect with feeder buses at stations along the length of the corridor to transfer passengers onto suburban routes. New light rail vehicles were to be bought to replace the ageing 1929 H-Class vehicles. However, public opposition to the project was broad; the Adelaide City Council objected to the plan on the basis that it would interfere with the well-designed layout of the city proper. In response, the Government altered the plan to redirect the line underneath the city, significantly increasing the cost. Residents in inner-city suburbs such as St Peters were concerned about the noise of the light rail vehicles, and protested against any disruption of the Torrens Gorge, which lies in the Modbury corridor. The Liberal MP for Torrens, Michael Wilson, representing the north-eastern suburbs, vocally opposed the project on behalf of his constituents.[9][6]
Drilling commenced on the tunnel, but the resignation in 1979 of popular Premier Dunstan weakened the Government, along with widespread bus strikes and public dissatisfaction with the light rail project. In elections held that year, the Liberal Party gained government with a swing of 11% in their favour. Wilson became Transport Minister in the new cabinet and construction of the light rail project was halted immediately.[9]
In search of a replacement for the light rail project, the new Government sent experts to examine an innovative guided bus system being developed in West Germany by Daimler-Benz for use in tram tunnels in Essen. After extensive consultations with German authorities, State Transport Department 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 12 kilometres (7.5 mi): initially only three kilometres (1.8 mi) 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. In 1982 the Tonkin Liberal Government that oversaw the O-Bahn's development lost office and was succeeded by the Bannon-led Labor Party resulting in uncertainty over the future of the project. The 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).[10][6][11] The cost of the project totalled $98 million, including the buses.[12]
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.[10] When the O-Bahn was completed in 1989, passenger numbers rose another 17%.[11] The Adelaide public transport system was privatised in the 1990s and overall patronage across all systems (bus, rail and tram) dropped 25%. The exception to this was the O-Bahn with no decrease, and there were 19,500 passenger trips daily in 1996 (7.13 million a year). Currently there are 22,000 passenger trips daily (8 million a year).[9]
There have been a number of proposals to extend the O-Bahn to Golden Grove and to the southern suburbs. An extension to Golden Grove would require the acquisition of extensive tracts of private property, in the absence of an available corridor. Population increase in the area is negligible, although sprawl continues from Tea Tree Plaza Interchange for another eight kilometres to the Adelaide Hills. The current route was built with an allowance for a station at Grand Junction Road but it has not been built.[13]
The southern O-Bahn proposal has 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.[9] The most suggested route for an O-Bahn has been for an alignment adjacent to the Noarlunga rail line from the city to the Tonsley branch line.[14][15] The O-Bahn would end there, with buses continuing on an upgraded (dual-carriageway) 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 tram overpass would require huge alteration.[16] The estimated cost of construction, AU$182 million, was considered too expensive, and the proposal was suspended in 2001.[17] The current Labor Government has focused on road upgrades and an inner-city light rail extension.[8]
The purchase of 160 buses at a cost of $120 million is to take place over five years from 2007 to 2012 to replace buses used on the O-Bahn and inner city routes where the fleet is near its 25-year age limit. With the contract expected to be finalised by June 2007, the first buses are planned to be delivered in 2008. Being replaced are the current $90 million contract for 170 buses won by Scania with Custom Coaches from 2001 over five years. With the new contract, Adelaide expects to be at 89% disability accessible by 2013 and fully accessible by 2022, and all buses will be air-conditioned by 2013. There are also plans to upgrade the O-Bahn track and interchanges with a new state of the art ticketing system. It is planned that weekday travel by public transport will double by 2018.[18]
The O-Bahn track is made of concrete; it is elevated above ground because of the poor quality of soils along the River Torrens, which frequently move due to seismic shifts. Large concrete pylons were drilled into the ground to ensure stability, to a depth of up to four metres. On top of the pylons are concrete sleepers on which the track runs. 5,600 pylons were drilled in place to support 5,600 sleepers and 4,200 prefabricated L-shaped track pieces, sited at 12-metre (40-ft) intervals. The width of both tracks, sitting on the sleepers, is 6.2 metres (20 ft).[19][20]
At the city end, the O-Bahn begins at Hackney Road, opposite the East Parklands, where it enters a 60-metre (200-ft) tunnel at a speed limited to 40 km/h (25 mph), due to the tight initial corner, ensuring that the rear tyres (especially trailer tyres of articulated buses) do not 'scrub' against the track. Speed is gradually increased to 80 km/h (50 mph) for most of the trip to Klemzig Station. Once en route to Paradise Interchange, the speed limit is 100 km/h (62 mph), with 90 km/h (56 mph) on tighter corners. The limit on the remaining section to Tea Tree Plaza Interchange varies between 100 km/h (62 mph), 90 km/h (56 mph), and 80 km/h (50 mph). The average speed including stops is about 60 km/h (37 mph). On some sections, 115 km/h (70 mph) has been easily achieved in tests. On entering interchanges the O-Bahn ends and the speed limit is 40 km/h (24 mph). In the interchange area, the speed limit is 20 km/h (12 mph).[9][13] The O-Bahn is officially considered a road, due to a court ruling in the early years of the system's operation. This ruling permits the South Australian Police to install speed cameras and fine speeding drivers.[9]
It is possible for cars to enter the O-Bahn from Hackney Road or at any of the interchanges. This is deterred by a large number of signs at entrance points and a "sump buster" device that rips out a car's sump (oil pan) if it gets onto the track. An average of four cars per year enter the O-Bahn and must be removed by crane.[9]
The first buses to enter service on the O-Bahn were specially modified Mercedes-Benz 0305 models. A fleet comprising 41 rigid and 51 articulated buses was purchased, their cost included in the original $98 million budget. The chassis were bought from Germany and heavily modified at the Mitsubishi Motors plant in Clovelly Park. The rigid buses had their power increased to 240 hp (177 kW) and the articulateds to 280 hp (207 kW); they were the first buses to travel at a speed of 100 km/h on suburban routes. Modified Scania and MAN buses were later introduced. All buses have ABS brakes and are able to stop within two bus lengths.[20][10][11]
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 bus 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 40 km/h (24 mph).[11][9]
The guide-wheel, which protrudes from the front sides and aligns with the track, is the most important part of the bus when travelling on the O-Bahn. Connected directly to the steering mechanism, it 'steers' the bus while on the track and prevents the main tyres from rubbing against the sides of the track. While it is not strictly necessary for drivers to hold the steering wheel when travelling on the O-Bahn because of the guide-wheel, safety procedures require the driver to be alert to their circumstances at all times. A rumble strip before stations is a reminder that they need to resume control. The guide-wheel is the most delicate part of the system and is designed to snap off upon sharp impact; before the O-Bahn was in place, a number of buses were fitted with guide-wheels for their ordinary routes to test their durability. Drivers were forced to be more cautious on their normal trips after numerous guide-wheel-to-kerb impacts.[11][9]
Klemzig Station is the first station, three kilometres (1.8 mi) from the city centre in the suburb of Klemzig, Payneham. It was built as a connector to the city loop 'Circle Line' bus service, which follows the Adelaide outer ring route, not as a bus interchange. Many bus services bypass Klemzig and the station has limited capacity. It contains a "Park 'n' Ride" carpark with 165 parks that is currently being expanded.[21][9]
Paradise Interchange is the second station, six kilometres (3.7 mi) from the city centre, in Paradise, Campbelltown. The terminus before the completion of Stage 2, it is now served by buses from suburban streets, and has 625 carparks.[22]
Tea Tree Plaza Interchange is the terminus, 12 kilometres (7.5 mi) from the city centre, in Modbury, Tea Tree Gully. Adjacent to the Tea Tree Plaza shopping centre, 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 500 carparking spaces.[23]
The O-Bahn uses the standard Adelaide Metro ticketing system. Single-trip adult tickets are subsidised by $2.90 by the South Australian Government, compared with the $8.80 subsidy for a journey on the rail system. Tickets are sold at interchanges and on buses. There are different fares for students and concession-card holders and at off-peak times.[24]
A standard peak ticket costs $4.20 and an off-peak single-trip ticket costs $2.60[25] and is valid for two hours. Unlimited day ticket ($8.00) and 10-use multi-trip tickets ($27.80) are available. The prices for single trip concession tickets are $2.10 on peak and 1.20 off peak. Tickets can be used across all Adelaide Metro services, including trams and trains; they require validation upon entry to a vehicle. Failure to produce a ticket incurs a $210.00 fine.[26]
From the start, the construction of the O-Bahn—rather than the previously touted Modbury Freeway—was motivated by a desire to reduce car dependency. Six million dollars of the total cost 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. Arising from environmental considerations, the O-Bahn is carbon-neutral.[12][27]
The original buses ran on diesel fuel, but the system allows for newer buses that run on alternative energy sources. Biodiesel fuel was trialled between July 2005 and May 2006. Buses using natural gas have been trialled, although they have not seen regular usage due to a perceived lack of power, especially on the section of the down track immediately after Paradise Interchange where the track rises sharply. The design of the O-Bahn provides for the installation of overhead wires for trolleybuses.[20]