ULTra (rapid transit)

An ULTra Pod at Heathrow Airport, London

ULTra (Urban Light Transit) is a personal rapid transit system developed by the British engineering company ULTra Global PRT (formerly known as Advanced Transport Systems).

The first public system using ULTra opened at London's Heathrow Airport in May 2011. It consists of 21 vehicles operating on a 3.9-kilometre (2.4 mi) route connecting Terminal 5 to its business passenger car park, just north of the airport. An urban ULTra system opened in Amritsar, India, in December 2011, with over 200 pods running on an 8-kilometre (5.0 mi) elevated guideway serving seven stations.

To reduce fabrication costs, the ULTra uses largely off-the-shelf technologies, such as rubber tires running on an open guideway. This approach has resulted in a system that ULTra believes to be more economical; the company reports that the total cost of the system (vehicles, infrastructure and control systems) is between £3 million and £5 million per kilometre of guideway.

Inception

The system was originally designed by Martin Lowson and his design team, Lowson having put £10 million into the project. He formed Advanced Transport Systems (ATS) in Cardiff to develop the system, and their site later served as the location for building its test track. ULTra has twice been awarded funding from the UK National Endowment for Science, Technology and the Arts (NESTA). Much of the original research on ULTra was done by the Aerospace Engineering department at the University of Bristol during the 1990s. Recently the company renamed itself to "ULTra PRT Limited" to better reflect its primary business, and moved its corporate headquarters to Bristol.

Background

Past PRT designs

The personal rapid transit, or PRT, originally developed in the 1950s as a response to the need to move commuters in areas where the densities were too low to pay for the construction of a conventional metro system. Using automated guidance allowed headways to be shortened, often to a few seconds, but in some cases fractions of a second. This increases the route capacity, allowing the vehicles to become much smaller while still carrying the same passenger load in a given time. Smaller vehicles in turn would require simpler "tracks", smaller stations, and lowered capital costs as a result. Smaller towns and cities that could never hope to fund a conventional mass transit system could afford a PRT, and the concept generated intense interest.

Numerous PRT systems were designed in the late 1960s and early 1970s, many as a result of the publication of the highly influential HUD reports. In general, these systems intended to use small four to six passenger vehicles, but most evolved to larger designs over time (see Alden staRRcar). As they did so, vehicles and tracks grew heavier, capital costs rose, and interest dropped. In the end, only one production PRT system was ever installed, the Morgantown PRT, a government-funded demonstration system to prove the concept. Originally derided as a white elephant, the Morgantown system has since proven itself both reliable and relatively low-cost.

ULTra

In the time since the Morgantown system was installed, general technological improvements have led to a number of ways to lower the cost of implementing a PRT system. One of the simplest, but most profound, was the development of more efficient, reliable and quick-charging battery systems. Older PRT systems used electricity fed from track-side conductors in a fashion similar to a conventional metro, but these can be eliminated in favour of batteries that quickly charge up at stations or small charging strips along the route. Another change is the moving of the guidance logic from centralised computers to on-board systems of dramatically improved performance, allowing the vehicles to steer and switch themselves between routes on their own. This eliminates the need for a track-mounted guiderail able to steer the vehicle (see, for instance, the Ford ACT). Together, these changes mean the vehicle no longer needs strong mechanical contact with the guideway, which can be dramatically reduced in complexity.

In the case of ULTra, the guideway can consist of as little as two parallel rows of concrete barriers, similar to the bumpers found in a parking lot. The vehicle uses these for fine guidance only; it is able to steer itself around curves by following the barriers passively. No "switching" is required on the track either, as the vehicles can make their own turns between routes based on an internal map. Since the vehicles are battery powered, there's no need for electrification along the track. Instead the vehicles recharge when parked at the stations. As a result, the trackway is similar in complexity to a conventional road surface - a light-duty one as the vehicles will not vary in weight to the extent of a tractor-trailer. Even the stations are greatly simplified; in the case of ground-level tracks, the lack of any substantial infrastructure means the vehicles can stop at any kerb. Stations at Heathrow resemble a parking lot with diagonal slots, with a rain shield similar to the awnings at a gas station.

For all of these reasons, the capital costs of the ULTra system are dramatically reduced compared to older systems. A 1980s Canadian estimate places the price of a conventional underground metro system at $75 to $80 million per kilometre, about CA$190 million in 2008 dollars. The Morgantown PRT came in well over-budget and has a demonstrated cost of just over US$9 million per km in 1979, equivalent to about US$28 million in 2008. Expansion plans from just after 2000 puts the costs of additional track at US$30 to US$40 million per mile. However, the company estimates that an ULTra system can be installed, including vehicles and stations, for £3 to £5 million per km of track, about US$5 to US$8 million, as of 2009. This cost includes extensive sections using elevated guideways, which are much more expensive than at-grade versions.

Following its successful launch there are now plans to extend it to the rest of the airport and even to the nearest town of Staines-upon-Thames, which is home to many of the airport's staff.

System description

Vehicles

The electric-powered vehicles have four seats, can carry a 500 kg payload, and are designed to travel at 40 kilometres per hour (25 mph) at gradients of up to 20%, although the company has suggested limiting operating routes to 10% gradients to improve passenger comfort. The vehicles can accommodate wheelchairs, shopping trolleys and other luggage in addition to the passengers.

Each pod is powered by four car batteries providing an average 2 kW of power and adding 8% to the gross weight of the vehicle. Other specifications include a 5 metre turning radius, an energy requirement of 0.55 MJ (megajoules) per passenger kilometre, and running noise levels of 35 dBA at 21.6 kilometres per hour measured at a distance of 10 metres.

The company has also developed designs for a freight version of the vehicle. This has the same external appearance as the passenger version, but its entire internal space is adapted to host a cargo capsule. These can be valuable in airport environments, where the network can be used to haul small freight.

Test track

The ULTra PRT test track in Cardiff.

The one-kilometre ULTra test track was launched in January 2002. The $4 million funding for the test track came from various sources in the United Kingdom government. One electric vehicle was demonstrated running at speeds up to 25 miles per hour. Accurate stopping was demonstrated and the vehicle ascended and descended a steep gradient. A single, rudimentary ground level station was shown.

Most of the test track guideway is at ground level. It is stated that in a commercial application, 90-percent or more of the guideway might have to be elevated. This elevated guideway is about 1.5 metres wide. According to a study of a hypothetical city-based installation, consisting of 19.8 kilometres (12.3 mi) of guideway (89% elevated), the total cost of ULTra track and associated civil engineering works is estimated to be £2.9 million per kilometre ($8.7M/mi). Per-station costs were estimated to be £0.48-million ($0.89M). Vehicle costs were not considered in this study.

Heathrow Terminal 5

The ULTra guideway under construction, with Terminal 5 in the upper left of the shot.

The first ULTra system began passenger trials at London Heathrow Airport, Terminal 5, in October 2010 and opened for full passenger service 22 hours a day, 7 days a week, in May 2011. Operational statistics in May 2012 demonstrate >99% reliability and an average passenger wait time over the one year period of 10 seconds. Ultra has achieved a number of awards from the London Transport Awards^{[citation needed]} and the British Parking Awards^{[citation needed]}.

It connects Heathrow Terminal 5 to its business passenger car park, just north of the airport, by a 3.9-kilometre (2.4 mi) ULTra PRT system, which was built on behalf of BAA, the airport's owner and operator. The system cost £30 million to develop.

Construction of the guideway was completed in October 2008. The line is largely elevated, but includes a ground level section where the route passes under the approach to the airport's northern runway. Following various trials, including some using airport staff as test passengers, the line opened to the public in May 2011. At that time it was described as a passenger trial. As of May 2011 it is fully operational and the bus service between the business car park and Terminal 5 has been discontinued. The pods use 50% less energy than a bus. It runs 22 hours a day. Operational statistics in May 2012 demonstrate >99% reliability and an average passenger wait time over the one year period of 10 seconds. Unlike all UK road and rail traffic which drive on the left, the PRT system drives on the right. In December 2012 the system passed the 500,000th passenger milestone.

The developers expect that users will wait an average of around 12 seconds, with 95% of passengers waiting for less than one minute for their private pod which will travel at up to 40 kilometres per hour (25 mph). If the pilot project is successful, BAA have indicated that they will extend the service throughout the airport and to nearby hotels using 400 pods.

Gurgaon City transport, India

In March 2010, the government of Haryana said that they are looking into a proposal to deploy the ULTra PRT system for rapid commuter transport in the city of Gurgaon. The city is looking at over 10 to 12 individual routes covering a total distance of approximately 100 kilometres (62 mi).

References

Bibliography

• Isaiah Litvak and Christopher Maule, "The Light-Rapid Comfortable (LRC) Train and the Intermediate Capacity Transit System (ICTS): Two Case Studies of Innovation in the Urban Transportation Equipment Manufacturing Industry", University of Toronto/York University Joint Program in Transportation, 1982
• A.D. Kerr, P.A. James (Ove Arup and Partners), C.V. Cook, A.P. Craig (ATS Ltd.) (May 2005), Infrastructure Cost Comparisons for PRT and APM, ASCE 10th International Conference on Automated People Movers 

External links

• Official website
• "Cardiff County Council Environmental Scrutiny Committee Meeting held 25 June 2002"
• Test track aerial image
• Robert Llewelyn explains the system and talks to the main people in an episode of the web series 'Fully charged'

,