David Crawford explores a high-level option of public transport.
Sharing its origin with that of ski lifts at winter sports resorts in the European Alps, urban aerial cable transport is attracting growing interest as a low-footprint, low-energy alternative to conventional public transport that can swoop over ground-level traffic congestion. Improved access to city centres from outlying or low-income suburbs is a typical driver.
Latin America has been notably quick to see the potential, following the pioneering Metrocable in Medellín, Colombia, which opened in 2006. Interest is also growing in Africa and elsewhere as European operators gear up to exploit potentially lucrative new markets.
In January 2015, for example, Paris regional public transport operator
Comments Poma management board chair Jean Souchal: “This agreement will leverage our position as effectively as possible at a time when there are many urban projects in development both in France and internationally.” A spokeswoman told ITS International: “RATP and Poma have already identified some projects of mutual interest but it is too soon to reveal specifics.”
December 2014 saw the emergence of a joint venture between Poma and two Algerian public transport operators in the largest country in Africa, the Arab world and the Mediterranean region. Poma is currently close to completing a six-stop link between the Algerian city of Tizi Ouzou and its suburbs.
The approach is widely seen as being appropriate to the topography of cities that lie between wide-spread valleys and hills, and the government is devoting substantial resources to it.
Further south in the continent, work began in November 2014 in Lagos, Nigeria, on a 12km mainland-islands cable car link to overcome congestion on existing bridge connections. A key aim is to cut emissions in a state where 200,000 additional vehicles are registered each year and add to a fleet that is responsible for 70% of regional air pollution. The local tally of 222 vehicles per km of road far outweighs the national average of 11. Meanwhile, the World Bank has authorised a US$175 million financing loan for a cable car project currently subject to a feasibility study for Kampala in Uganda, which could be operational by 2017.
Americas
Adding to the installed base of systems in Latin America, December 2014 saw the completion in Bolivia of the 10km-long Mi Teleférico (My Cable Car) system, claimed as the world’s largest urban cable car network. It carries up to 8,000 riders per hour in each direction between the Bolivian capital, La Paz, and the nearby city of El Alto (once a suburb), both lying high in the Andes Mountains and collectively home to some two million people. On leaving La Paz, the car has to rise almost 500m to reach its cliff-edge destination - the world’s highest major metropolis at an altitude of 4,150m. The government-financed system has been built by the Austrian
Saving around an hour on the road trip, it is expected to slash the endemic congestion that delays buses and the white minivans that currently serve as the major form of mass transport in the area, substantially cutting air pollution in the process.
With higher than expected levels of take up, Mi Teleférico expects the scheme to pay for itself within 25 years rather than the originally estimated 40. Adds Doppelmayr general manager Javier Telleria, “cable cars are a natural fit. The only options are to undertake huge infrastructure projects, demolish many homes and build new roads – or install cable.”
The US is, by contrast, relatively new to the cable car concept, the most recent example being the 2006 Portland Aerial Tram in Oregon, built by Doppelmayr. This links the main campus of the Oregon Health & Science University on Marquam Hill - the city’s largest employer and a major medical destination visited by 20,000 people a day – with a major downtown transport intrerchange near the emerging Southwestern leisure district.
Next in line could be the Texan state capital, Austin, the subject of a proposal by San Francisco-headquartered technology innovators Frog Design for a system to connect neighbourhoods and enable pedestrians – and cyclists - to hop over congested areas. The cabins would be detachable, to allow for a more intensive service during rush hours.
Down to earth
Ground-level versions of cable haul, or ‘flat funiculars’, use technologies such as air levitation, originally devised for 1970s ‘hovertrain’ schemes. These rivalled alternative magnetic levitation (maglev) proposals by supporting vehicles on air pads protected by rubber skirts and maintained under pressure by onboard compressors, fed by an external trackside power supply.The concept has now reappeared in developments such as Poma’s surface-level cable haul system (called MiniMetro) at Egypt’s Cairo International Airport, the second largest in the continent after Johannesburg, with a 2013 throughput of 22 million passengers.The €60 million (US$68 million), almost 2km-long service has a capacity of 2,000 riders per hour in either direction. It meets the airport’s quest for an efficient new link between three terminals, car parking and a shopping centre, for some 8.5 million passengers per year.
At Miami International Airport in Florida, US, group member Leitner-Poma is installing a MiniMetro to replace a conventional automated people mover between Concourse E and Satellite Terminal E. Completion of the first phase the US$87 million project is due by early 2016, the second following in 2017 and the system is expected to transport more than 30 million passengers every year.
Costs
Frog Design senior designer Michael McDaniel argues that aerial cable transit can be built for between US$1.9 million and US$7.5million per km, compared with U$21.9 million per km for a tramway. European industry sources suggest a starting point of €2 million per km (US$2.25 million per km) – the same as for bus rapid transit- against €15 million per km (US$17 million) per km) for a tramway. Costs tend to rise sharply for distances of over 5km.But Jonathan Powell, a researcher at the UK University of Newcastle’s Newrail transport research centre, warns that costs can “become very misleading, if quantitative results from specific projects (with their own unique characteristics) are generalised.”
When it comes to surface-level systems, air-cushion technology is likely to win out against any resurgence of maglev (magnetic levitation) alternative. Both typically use a concrete guideway (with associated land acquisition and construction costs), though the latter needs additional coils, magnets and plates embedded in or attached to it.
The costs of energy for running the air compressor work out similar to those of overcoming the rolling resistance of steel wheels on steel rails, and hence are rather lower than those of pneumatic-tyred vehicles, as in bus rapid transit. Says Powell: “The principal advantage of air cushion systems over conventional rail vehicles is therefore not a reduction in energy use, but a simplified track system with low contact forces and very little wear.
Criteria for success
At the July 2011 Third World Planning Schools Congress in Perth, Austrialia, Peter Brand of the Universidad Nacional de Colombia and Julio Davila of University College, London, UK, highlighted three key factors for success for aerial systems in low-income urban area applications. Cities planning installations, they said, must ensure:
• Topography and settlement patterns which inhibit conventional
high-capacity public transport systems;
• The presence of consolidated housing areas where qualitative
improvement in conditions are possible; and
• Governance structures that facilitate rapid and coordinated
implementation.
They go on to warn that: “the quick fix approach motivated by short-term political impact and publicity-conscious gain are unlikely to be successful.”
This last advice clearly has relevance beyond the bounds of low-income communities. It came a year before the opening of London’s high-profile, £60 million (US$90 million) cross-river Emirates Air Line cable link, built by Doppelmayr for the 2012 Olympic Games. Recent figures suggest that this service carries few regular commuters with the vast majority of users being tourists and sightseers. Green politicians have called for it to be relocated, to serve the busy Canary Wharf business district.
