Posts Tagged ‘capacity’

World’s First and Largest Urban PRT System Announced

Tuesday, December 13th, 2011

 We are posting ULTra Global’s recent press release here due to its significance. This is not an endorsement of ULTra over any other PRT system, only a recognition of the significance of this milestone for PRT in general.

The Punjab Government has awarded a contract for the world’s first urban Passenger Rapid Transport (PRT) system in Amritsar, India to Ultra Fairwood.  

At peak capacity the PRT system can carry up to 100,000 passengers a day on a 3.3km elevated guideway in over 200 specialist vehicles between seven stations, making it the world’s largest PRT system to date. 

Elevated Guideways

Elevated Guideways

Financed entirely by private funding on a build, own, operate transfer (BOOT) basis, the passenger services will go live in 2014. 

Although the cost of the scheme is subject to commercial confidentiality, it demonstrates that a large scale urban PRT system can be delivered on a financially viable, fare-based model and offer very real returns for financial backers.

The Ultra PRT system uses driverless, electric-battery powered, computer driven, zero emission vehicles called “pods” which :

  • can each carry 4-6 people in privacy and comfort
  • provide an on-demand, non-stop journey to anywhere on the system
  • use one third of the energy of a car,  and are virtually silent with no emissions
  • travel on a segregated guideway that can run over/alongside roads, rail tracks and buildings
  • never get held up by congestion, so reduce travel time
Bi-level Station

Bi-level Station

Amritsar is home to the holiest shrine of Sikhs, the Golden Temple, and is rich in historical, religious and heritage sites.  As such it’s a big draw for large numbers of visitors, especially during festivals and religious events, as pilgrims flock to the area.  Up to 500,000 people visit the Golden Temple on important religious festival days.  The PRT system will ease congestion and reduce the current long travel transit times.

The route will focus on taking passengers from the railway and bus stations to the Golden Temple and will:

  • take  35% of daily visitors to the Golden Temple
  • save up to 30 minutes on the current journey times
  • attract passengers from a wide geographic and demographic profile, from regular commuters to “one off day trip” users.
  • run from 04.00 – 24.00 seven days a week
  • charge fares competitive with alternative modes such as taxis and autorickshaws. 

 “The Punjab Government and city of Amritsar are leading the world in the application of a PRT system to provide volume transport in a major city environment.  As a result Ultra Fairwood is also in discussions with the authorities in other major Asian cities which suffer from major transportation infrastructure issues – congestion, space constraints, pollution problems, capacity restrictions and passenger service issues. The Ultra PRT system can help to solve these issues. 

“In one city by installing a PRT system we could potentially reduce a current journey of up to one hour in peak hours to around  seven minutes, in another country we may be able to reduce the number of cars on a major city’s streets by up to 20%.  People are at last starting to understand how this innovative technology can play a role in city transport solutions” said Ultra Fairwood’s CFO and Deputy CEO Alan Moore.

A sentiment echoed by Fraser Brown, MD of Ultra Global PRT, “The pod PRT system is an idea whose time has well and truly come.  Using British technology and know how, we’ve proved it works at Heathrow and now with Fairwood we’re creating bigger systems, on larger  routes, with more stations and pods. 

“We’ll be carrying 35% of the visitors in the area and removing 2.2m car trips in Amritsar per annum. It’s the future of environmental green travel. 

“Research has shown that by 2020, there could be between 50 to over 600 PRT system installations world wide. A real achievement for a system that came out of research from Bristol University.”

“Ultra Global sees the confidence that the Punjab Government have shown in PRT as further evidence of the growing sentiment amongst architects, transport planners and governments that PRT systems can sustainably and quickly transform an urban transport environment and provide users and other stakeholders with another viable transport mode in which to manage their cities and campuses.” Brown adds.

Ultra Fairwood is a collaboration between Ultra and Fairwood created in 2010 bringing the revolutionary Ultra technology to Asia.   Ultra Fairwood conceives, designs, finances, constructs and operates complete PRT solutions, typically on a BOOT basis.  The company is working on PRT projects for cities, campus environments and airports.

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Some Thoughts on Group Rapid Transit

Wednesday, June 29th, 2011

The Morgantown PRT system which has been operating in Morgantown West Virginia since 1975 is actually a group rapid transit system (GRT). GRT systems have larger vehicles and passengers are typically required to share rides with others going to the same destination(s). These vehicles also typically accommodate standees thereby fitting more passengers into a smaller space. As accustomed as we are to large trains and buses, many believe that larger GRT vehicles make more sense than smaller personal rapid transit (PRT) vehicles. But do they?

Morgantown PRT

Morgantown PRT

The answer is not simple. It depends on many factors. Larger vehicles require larger stations and more substantial guideways. Thus, the capital costs can be higher. The operating savings resulting from carrying more passengers in fewer vehicles can be offset by the additional cost of running larger empty vehicles during off-peak periods.

Because of the standees, GRT vehicles cannot accelerate or decelerate as quickly as PRT vehicles can. This requires greater separation (headway, or time between vehicles) in order to meet the same safety criteria. This in turn means that GRT’s capacity gains are less than would be expected by just comparing vehicle capacities.

2getthere GRT

2getthere GRT

GRT cannot match the high level of service of PRT where everyone gets a seat, nobody waits for more than about a minute and trips are nonstop. With GRT, seats are in relatively short supply. Passengers have to wait (typically up to about five minutes) for other passengers to fill the vehicle. In addition each vehicle may make a number of stops along the way.

The requirement for GRT vehicles to wait for passengers to arrive who all share the same destination(s) means that GRT does not function very well when there are numerous stations in a system. Either the wait times get quite long or most vehicles are nowhere near full.

Nonetheless, GRT can carry more passengers per hour along a guideway. Increased guideway capacity can be a useful attribute for a networked PRT system where there is intense demand between a few station pairs, but the majority of the demand can be handled by PRT vehicles. In this scenario, GRT service between the busy station pairs can be integrated with PRT service elsewhere. If the GRT vehicles can run on the PRT track, it could be feasible to intermingle the vehicles, changing the fleet mix to meet demand fluctuations. Vectus is developing a GRT vehicle that will run on their PRT track. Another solution that could achieve a similar result could be to platoon PRT vehicles together (either physically or electronically). Forming and breaking the platoons in stations could eliminate safety issues associated with doing so on the fly.

Personal rapid transit systems may be well advised to develop ride sharing/platooning/GRT options to meet the capacity demands that are bound to arise as applications become larger and more diverse. Some may bemoan the need to sacrifice some of the “personal” aspects but, in many countries, the demand for mass transportation will predominate. The distinction between PRT and GRT may become blurred.

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Personal Rapid Transit Capacity

Sunday, January 9th, 2011

The burgeoning interest in personal rapid transit (PRT) in India is highlighting the issue of PRT capacity. This is a fairly complex topic that will be dealt with fairly briefly here. Note: network capacity is much more complex than just the guideway capacity that is dealt with here. PRT capacity is complex because it is impacted by a number of issues:

Brick wall stopping (BWS) criteria. This is a railroad safety criterion that many believe not to be applicable to PRT. Basically BWS requires that a train must be able to stop before hitting a preceding train if that preceding train instantaneously turns into a stationary brick wall. In order to meet BWS the time between trains (or T-Pods in the case of PRT) must be adjusted based on speed and the maximum available, or allowable, deceleration.

Deceleration. The maximum deceleration is a function of the available friction and of whether passengers are standing or sitting, wearing seat belts, etc. The available friction or deceleration force varies with the type of PRT system. PRT systems driven and decelerated by linear induction motors rely on their motors for their primary breaking force and are typically independent of friction and thus weather. The maximum breaking deceleration they apply is typically less than what is available. Rubber-tired PRT systems, on the other hand, are dependent on the friction between their tires and the riding surface which can be dramatically impacted by weather. These systems will usually have weather mitigation plans aimed at maintaining friction above about 0.25G where G is the force of gravity.

Minimum headway. This is the minimum time between vehicles measured from the front of one vehicle to the front of the other. For BWS criteria, it varies from about 1.4 seconds with 0.50G deceleration force at 15 mph to about 3.2 seconds with 0.25G deceleration force at 30 mph. Without BWS criteria many suppliers claim they will achieve minimum headways of 0.5 seconds. Cabintaxi demonstrated 0.5 second PRT headways but never proved endurance or safety at these headways. We therefore believe it prudent to plan for minimum headways of no less than 1.0 seconds. Headway is strongly tied to capacity since reducing headway by half theoretically doubles capacity.

Occupancy. This is the number of passengers per T-pod. Occupancy is also strongly tied to capacity since doubling the occupancy theoretically doubles capacity. However increasing PRT occupancy during peak hours usually involves ride sharing. This can be easily accomplished on small systems with few stations but is difficult to accomplish on large systems with many stations. Imagine how long a passenger bound to station 57 in a 100 station system would have to wait for another to arrive also bound for station 57. Ride sharing protocols to overcome this problem will be the subject of a future article.

The table below provides the theoretical guideway capacity in passengers per hour based on variations in the parameters discussed above. The reasonable capacity of PRT guideways is seen to range between about 1,000 and 14,000 passengers per hour. Since PRT systems tend to cost much less than other fixed guideway systems, it is usually useful to compare the costs required to meet the capacity demand.

Capacity2

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