Automated metro systems set to overtake
E&T looks at the effectiveness of driverless trains - are they ready for general roll-out?
Passenger screen doors enhance safety and reduce the risk of obstacles on the metro tracks
London's DLR currently operates driverless trains with attendants in stations and on the platform
Automated systems can decrease travel time, releasing more trains in peak periods and fewer during quiet times
Fully automated metro lines top the procurement lists of many transport planners across the world. But how effective are they?
The driving party-lines behind both of London's Mayoral electoral candidates this year have included a focus on improving London's ageing underground system. Olympic fever has seen many banks and trading floors encourage their workforces to operate from home during the summer months, fearing congested scenes of commuter carnage. Ambitious changes to the Tube are, of course, far too late for this summer's Games, but the event has done a great deal to highlight the importance of upgrading existing systems to enable it to cope better with booming urban populations.
Many in the transport industry believe the rejuvenation of the Tube lies in the technology of automation. As a result, driverless trains, platform screen doors and fully automated systems now top the procurement lists of transport planners across the world. However, London's DLR line was met with a mixed reception following its early performance in the 1980s, and last year London Mayor Boris Johnson's bullish plans to replace London's Tube train drivers with automated systems was met with a frosty reception from the press.
The heart of the city
The metro is a concept that has been around for more than a century. Some 116 systems are now active in cities around the world and the very first, now operational as the Metropolitan Line, opened in London over 120 years ago.
Although classed as premium investments, metro systems are still perceived to be a worthy asset by transport planner, as they are considered the most efficient mode of transport in regards to energy consumption and passenger occupancy. As 560 cities across the world reach a population of one million before the year 2015, some of the larger metro systems, such as that in Paris, are looking to automation for economy, safety and reliability.
Wide-scale automation, whether it is full or driverless, has been considered the biggest major development in metro technology over the last 20 years. Currently, 30 fully automated metro lines have been integrated into networks across the world, and UK company Bombardier has provided automation solutions for many of these forward-thinking cities, including Paris and Vancouver. Thomas Siegemund, director of mass transit for the organisation, compares the metro system to capillaries in lungs: "The fast flow of a metro transport system helps a city to breathe."
The growth rate in which automation has penetrated the transport market is impressive. By 2020, around 75 per cent of new metro lines will be fully driverless, with 40 per cent of driven metro lines retrofitted to fully automated.
Some 519km of automated metro line is now operational across the world, taking in 535 stations in 25 different cities including Paris, Barcelona and Copenhagen. Cash-rich Asia currently leads implementation of automated metro systems, with around 40 per cent of the world's automated lines now spanning the continent.
Three different types of automated metro system are currently recognised. Semi-automatic train operation (STO) is partially controlled by a driver onboard, operating the stopping of the train, door closure and driver-to-passenger communications. Driverless train operation (DTO), implemented on the DLR in London, is a more sophisticated system and has been adopted most widely across the world. It eradicates the need for a driver, but employs a train attendant to supervise door closure, ticket inspection and passenger-to-controller communications. Much higher security control must be implemented in these systems. Unattended train operation (UTO) is seen as the next step, with systems relying entirely on instruction from the control centre.
The automated movement
The primary motivations for automated metro systems are faster services, economy, safety, and energy efficiency. Although already deemed the most efficient mode of passenger transport, traditional metro systems can be improved by increasing passenger capacity, shrinking headway time to a mere 60 seconds. A recent survey by Frost & Sullivan revealed passengers would be prepared to pay up to 25 per cent more for their ticket if their destination was reached in half the time.
Reducing intervals between trains – a process called headway timing – is deemed to be the ideal solution by deploying additional trains into the system at peak hours. However, in many metro systems this also requires additional standby staff, which raises employee costs.
Automatic systems can respond immediately to congestion, deploying more carriages without the need for extra staff, explains Frank Gerken, mass transit manager for Siemens. "The frequency of the trains can be enhanced, especially in low-traffic hours, as more and shorter trains can be inserted in traffic without the need for more operational staff."
This notion of capacity on demand, Siegemund says, is what is driving the transport industry's widespread adoption of automation. "An automatic system can adapt immediately to an influx in passenger demand, altering the size and frequency of the trains," says Siegemund. "One of our customers pointed out that the problem with the network at the moment is that there are not only too few trains, but there can also be too many. He didn't want to pay to 'transport warm air from station to station'. Automation can address this problem also."
Safety and efficiency
Improved safety is also a major reason for installing automated services. Automation removes the human element from the system, eradicating the risk of human error. Gerken says that safety improves with increased automation as computerised systems control train movements more precisely than humans. "Surrounding systems for the passengers' safety were not economically available in the past, but today onboard CCTV, platform supervision, onboard emergency calls and onboard telemetry is available, including remote train-diagnosis."
Sensors and detection is where much of the new safety technology lies, including precise door-gap and fire detection monitoring. Intrusion detection technology features integrated optical sensors, which are activated when a passenger strays on to Tube lines, but while the technology is considered effective it is also deemed an excessively sensitive application by some in the industry. Obstacle and intrusion detection on automated lines can be increased by up to 10 times when installing optical sensors says Didier Bense, director of Société du Grand Paris, but unfortunately these warnings are often unrelated to passenger movement and can be attributed to animals or waste on the tracks.
One simple solution to this issue lies in another automated system passenger screen doors. Copenhagen's 21km metro system, though small in comparison to the likes of Paris and London, uses this technology and is a perfect example of fully automated technology at its best. The line carries 54 million passengers a year, a fraction of London Underground's one billion remit, and comprises of a combination of light railway lines and an underground metro system.
The city uses passenger screen doors, automatic outer safety doors that do not allow the passengers direct access to the tracks, on its underground trains and has seen system failures decrease by approximately one-third. Passenger screen doors also have additional operational criteria, such as air-conditioning monitoring.
Improved energy efficiency on automated lines is also an attractive incentive for cities attempting to cut carbon emissions. Few automated metro systems can contest Stockholm's energy boast – the city's metro runs predominantly on renewable energy generated by wind, with its bus network running on bio-gas and methanol – so instead, other energy-efficient tactics are needed to reduce carbon emissions.
Automated trains use less energy thanks to optimised acceleration, traction and braking processes. LED lighting has also become a common standard throughout newer models of automatic trains, decreasing the amount of energy consumed, meaning energy consumption can be slashed by up to 30 per cent.
Money in the bank
The benefits of automation come at a cost, which is why many European countries have been reluctant to invest in recent years. But in the long-term, automation is actually much more economical than a manned system, says Gabriel Colceag, vice-president of urban rail signalling at Thales. "Over a period of 20 years, a UTO or DTO system would actually be cheaper than an STO system. But in no circumstances should an automation network be overloaded with legacy equipment."
The risks with overloading automated systems in this way can be avoided with early adoption of DTO or UTO in the lifecycle of a metro system, as it will result in lower initial investment with shorter implementation time. No modification of existing cabs would be needed and a single training and operation procedure would be required. But for most existing manned metro systems a retrofit adoption is the only option. Cabs must be modified to remove the existing driver cabin, while out-of-service trains may cause costly delays for operators.
One of the most arduous tasks is to retrain an entire workforce on new systems, equipment, wiring and hardware, many of whom may not yet be of sufficient skill level to adapt to these new technologies, incurring additional training costs.
This development is not only a technological challenge, but also requires a complete rethink of service philosophy, organisation, and staff qualifications.
From a human point of view, the highest cost for many will be their jobs. Drivers will be replaced with automated systems, meaning many roles will become redundant. In an ageing society, Siegemund says, it has become difficult to hire and retain train drivers, particularly in areas like Berlin where a lack of drivers has been reported due to the shifting perception of the role of the train driver. "The romance of being a train driver has dissolved. Training staff to control automation is a more professional incentive for most people, so motivated drivers can be retrained to use more sophisticated software systems. Overall, this is a much more attractive career path than driving in a tunnel."
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