- Train overspeed. An Introduction To Airport Apm Systems. Dennis M. Elliott Jack Norton. - - Safe train separation Unauthorized train movement

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1 Journal ofadvanced Transportation, Vol. 33, No. 1, pp An Introduction To Airport Apm Systems Dennis M. Elliott Jack Norton The purpose of this paper is to provide an introduction to the nature and purpose of airport automated people mover (APM) systems. Our objective is to provide a convenient research tool for persons seeking an introduction to the airport APM industry. Included are illustrations of typical system designs; a listing of existing airport APM systems, including a tabular presentation of selected data; an organization and discussion of the history and evolution of the existing systems; and a status report on current developments in the APM industry. Definition Of Automated People Mover System An automated people mover (APM) system is a network of closed-cab vehicles or trains, designed for the purpose of transporting passengers. The vehicles or trains operate on dedicated rights-of-way and tracks, referred to as the "guideway." The system is automated in that there are no drivers on-board the vehicles or trains. The system is controlled or monitored by an operator from a remote central control room. Typically, the electro-mechanical design and physical characteristics of an APM are unique and proprietary to each manufacturer. Therefore, APM systems cannot, as a general rule, be interconnected, or share operating elements. The Chicago O'Hare Airport APM is shown in Figure 1. Movement of the APM vehicleshains is accomplished automatically, including starting, cruising, stopping at stations and opening/closing doors. Automatic control features, which assure system safety, include: 0 Automatic Train Protection (ATP) - - Safe train separation Unauthorized train movement - Train overspeed Detection of trains on guideway Dennis M. Elliott and Jack Norton are consultants at Lea + Elliott, Inc., Arlington, Texas, USA. Received July 1998; Accepted September 1998.

2 36 Dennis M. Elliott and Jack Norton Figure 1. Chicago O Hare Airport APM Parted train protection Unscheduled door opening Mergesafety Brake failure - Movement interlocks, including departure, reverse and propulsiodbraking interlocks 0 Automatic Train Operation (AT01 - Regulate train movement, including starting and stopping - Slowing as necessary for guideway alignment changes andor the presence of other trains - Stopping at stations, including openingklosing train doors 0 Automatic Train Supervision (ATS)

3 An Introduction to Airport APM Systems 37 - System performance monitoring, including location and movement of all trains - Performance control and override, including: initiation of system service, inserting and removing indwidual trains, modification of train routing, selection of operating modes, audio announcements, video surveillance, video recording, acknowledgment of traidsystem alarms, status of trains, stop all trains, terminate service System Characteristics Of Airport Apm Systems There are several distinctive physical and operational characteristics of airport APM systems. Normal modes of APM system operation include: Single Shuttle In single shuttle mode, a single train operates on a single, dedicated guideway connecting two stations. Normally, the train departs one station, accelerates to cruise speed, decelerates and stops in the other station. After a suitable dwell time for passengers to deboard and board, the train doors close, and the train departs the station, retracing its path to the original station. There, the above process is repeated. Usually, single shuttle mode operates totally automatically, without interruption. However, in periods of light demand, a variation of the automatic service, called "on-call single shuttle mode," may be used. In this mode, trains wait in stations until the presence of passengers in the station is detected. Upon detection of passengers, the train doors open, and shuttle service, as described above, is initiated. Either a oneway trip, or a round trip may be commanded, depending on where the train is located and where passenger demand is detected. A schematic diagram of a single shuttle system is provided in Figure 2. Figure 2. Single Shuttle

4 38 Dennis M. Elliott and Jack Norton Single Shuttle With Bpass A variation of the above-described single shuttle operation is sometimes employed in which the guideway is a single lane layout with a passing segment located at the midpoint. In this codiguration, two trains are operated on the single lane guideway in a coordinated fashion. The trains are synchronized to depart the end stations at the same time, headed for each other. However, as they approach the bypass area, one train is (mechanically) directed to follow one of the bypass lanes, and the second train the other. In this way, synchronized movement of two trains can be achieved with less guideway than if two independent single shuttles are used, with correspondingly less cost. However, this layout suffers from reduced availability if either segment of single-lane guideway is blocked or inoperable. Should this happen, the entire system can be rendered unusable by any passengers. A schematic diagram of a single shuttle with bypass system is provided in Figure 3. Svnchronized Dual Shuttle Figure 3. Single Shuttle with Bypass In a synchronized dual shuttle system, two trains operate on two adjacent single-lane guideways; each guideway is dedicated to the movement of one train. In this design, the two trains: (1) depart from opposite end stations at approximately the same time; and (2) arrive at the destination station at approximately the same time. Normally, dwell times at the stations are maintained to be equal, in order to maintain synchronized operation. After a suitable station dwell for passenger deboarding and boarding, the trains reverse direction and return to their original station. If the movement of either train is delayed, the system will operate temporarily in a non-synchronized manner; however, the automatic train operation (ATO) subsystem will reestablish synchronization in a minimum time by automatically altering the relative station dwells for the two trains, until synchronization is again established. As for the single shuttle mode, a synchronized dual shuttle system may also operate in an on-call fashion. An advantage of the dual shuttle system is it's inherent availability; if one of the two trains becomes inoperable,

5 An Introduction to Airport APM Systems 39 or its guideway is blocked, the other train can still operate normally, providing service at roughly half the previous level. A schematic diagram of a synchronized dual shuttle system is provided in Figure 4. Dual Shuttle With Bwass Figure 4. Dual Shuttle System The dual shuttle with bypass configuration consists of two, single shuttle with bypass systems located adjacent to each other, sharing stations located between the two guideways. By using this design, it is possible to have four operating trains on the two guideways, with corresponding increases in frequency of service and system capacity. A schematic diagram of a dual shuttle with bypass system is provided in Figure 5. Figure 5. Dual Shuttle with Bypass The loop mode of operation is just as it sounds; one or more trains operate on a closed loop guideway, serving several stations. Trains move around the guideway, stopping at each station in turn. Collisions between the trains are prevented by the automatic train protection (ATP) subsystem. Movement of trains is controlled by the autombtic train operation (ATO) subsystem. Normally, trains are kept equally spaced in time around the loop by operation

6 40 Dennis M. Elliott and Jack Norton of the automatic train supervision (ATS) subsystem. A schematic diagram of a loop system is provided in Figure 6. D = Pinched Loop Figure6. Loop The pinched loop mode of operation is similar to the loop mode, except that trains follow an elongated, parallel, dual-lane guideway alignment, usually having stations at each end, and one or more intermediate stations along the alignment. In most cases, the station platforms are located between the two guideways, so that, at a station, trains arrive and depart on both sides of the platform. In the pinched loop mode, trains typically depart one end station and proceed along the right-hand guideway, stopping at each intermediate station along the way, and at the opposite end station. The Denver Airport APM system shown in Figure 7 is an example of a Pinched Loop System. At each

An Introduction to Airport APM Systems 41 Figure 7. Pinched Loop System at Denver Airport station stop, train doors open and the train dwells to allow passenger deboarding and boarding.

7 An Introduction to Airport APM Systems 41 Figure 7. Pinched Loop System at Denver Airport station stop, train doors open and the train dwells to allow passenger deboarding and boarding. After dwelling at the opposite end station, trains reverse direction and depart the station; immediately after leaving the end station, the trains are diverted by switches through a crossover to the adjacent, parallel guideway for the return trip. (Note they are still on the right-hand side of the parallel guideways.) Upon reaching the end station of origin, the trains again dwell, then pass through another crossover to return to the righthand side of the dual-lane guideways. Then the above-described process is repeated. Normal operations are in a counterclockwise direction when viewed from above, for forward operations on the right-side lane of the dual-lane guideways. Sirmlar to the loop system, trains are normally kept equally spaced in time around the pinched loop system by operation of the automatic train supervision (ATS) subsystem. A schematic diagram of a pinched loop system is provided in Figure 8.

8 42 Dennis M. Elliott and Jack Norton Network Svstem Figure 8. Pinched Loop A network system differs fiom the above modes as follows: Typically, a network system includes a number of guideway segments (usually quite long), interspemed with switches that permit different trains to follow different paths through the network. Usually, a set of routes is devised and programmed so that some trains serve one subset of stations following a prescribed route, while other trains serve other subsets of stations following other prescribed routes. New or revised routes may be programmed as customer needs within the network change. The movement of all trains on a given route is controlled by the automatic train operation (ATO) subsystem (or sometimes, the automatic train supervision (ATS) subsystem) so that, at each diverge point, the train is instructed to follow either the left or right path through the switch, in order to follow its prescribed route. The only existing example of a network system is the Airport Train System at the DallasFort Worth International Airport. The configuration of that system is shown in Figure 9. Existing Airport Apm Systems At the time of this paper, there are twenty-two airports with operating APM systems. Selected data for these existing systems is provided in Figure 10. In addition, there are seven new systems that are preparing to commence service, or are in construction. Selected data for these new systems is provided in Figure 11. Finally, in addition to the systems described in Figures 10 and 11, there are many new APM projects in various stages of planning. These projects are so numerous and varied as to be beyond the scope of this paper.

9 An Introduction to Airport APM Systems 43 Noteworthy Airport Apm Systems Figure 9. Network The scope of this paper does not allow discussion of all of the airport APM systems. However, there are several systems that deserve special comment., either because of their unique historical contribution to the industry, or because of unique technical or operational features. The Definitive Pioneers From the list of active airport APM systems, four systems stand out as pioneering systems; ones that defined the airport APM industry as we know it today. Those four are: Tampa; Seattle-Tacoma; DallasRort Worth and Atlanta. Tampa International Airport - The dual shuttle systems operating at Tampa International Airport represent the first APM systems ever deployed at a major airport. These systems were supplied by Westinghouse Electric Company (now Adtranz), and were based on the demonstration system that Westinghouse had previously built and tested in South Park, Pennsylvania. Public service on these systems began in Since that time, four of the original vehicles have been replaced with new vehicles, and two new dual shuttles have been added. Tampa will always occupy a singular place in the evolution of airport APM systems. It represents a courageous decision by the Tampa airport planners to configure an entire new airport around the predicted performance

10 44 Dennis M. Elliott and Jack Norton AIRPORTAPMSYSTEMS Figure 10. Existing Airport APMs

11 --- Houston Lntercont. I999 Adtranz I Self Propelled I Dual Shuttle 1 I Newark Extension 2000 Admz Monorail Pinched Loop New York - JFK 2002 Bombardier MK I1 Self Propelled Looflinched Loop Paris CDG 1998 Soule SK - Cable Propelled Pinched Loop Rome Fiumicino 1999 Adtranz CX-100 Self Propelled Dual Shuttle San Francisco 2001 Adtranz CX-100 Self Propelled Looflinched Loop Zurich 2001 Otis Cable Propelled Dual Shuttle Figure 11. Airport APMs in Construction

12 46 Dennis M. Elliott and Jack Norton of an entirely new form of passenger conveyance. One of the main goals of the airport was to provide a minimum walk distance for the largely elderly users. Airport planners concluded that the only way to accommodate this goal was to utilize some sort of passenger conveyance system. Hence, the birth of the APM industry. Fortunately for Tampa and for the APM industry, the faith of the Tampa planners was not misplaced. The shuttle systems have performed their assigned task with high reliability. Because of this, and also because of the pleasing architectural design and amenities of the airport terminal buildings, Tampa is often cited by travelers as their favorite U.S. airport. Seattle-Tacoma International Airport - The APM system at Seattle- Tacoma International Airport (Sea-Tac) followed the Tampa system by a couple of years. It is a unique system because it represents the first deployment of a loop APM configuration. The significance of this lies in the additional complexity of the automatic train control system. In a loop system, trains must be protected fiom colliding with each other (this is not a requirement for a shuttle system on a dedicated guideway, as at Tampa). In developing the automatic controls for the Sea-Tac system, Westinghouse Electric engineers followed the "fail-safe" design principals that have become the standard for all modem APM systems. DalladFort Worth International Airport - The Airport Train at the DallasRort Worth International Airport, which opened for service in 1974, is unique for a number of reasons. First, it was the first network APM system built. To date, it is the only network system ever built. (At DFW, rather than all trains following the same path, individual trains follow different routes throughout the system, providing service to different stations.) Second, the Airport Train is the largest APM system ever built, with over 13 miles of operating guideway, 68 vehicles, and over 50 stations. Third, it was the first APM to incorporate operational switching. Finally, the DFW Airport Train represents an audacious attempt by its designers, Vought Aeronautics Corporation, to combine both passenger and goods transportation into one, integrated system. When it opened, the Airport Train transported the following classes of persons and cargo, each in separate vehicles, following separate routes: (1) airport passengers; (2) airport and airline employees; (3) transferring passengers' luggage; (4) airmail; (5) airport terminal supplies; and (6) airport terminal trash. All of the above services were successfully demonstrated

An Introduction to Airport APM Systems 47 and/or operated. For reasons that are beyond the scope of this paper, the goods services no longer operate.

13 An Introduction to Airport APM Systems 47 and/or operated. For reasons that are beyond the scope of this paper, the goods services no longer operate. However, the system continues to transport passengers at a high level of reliability. In 199 1, a portion of the wort Train was converted to a dedicated service between American Airlines two terminals; this service is called the American Airlines TrAAm. Figure 12. Dallas/Fort Worth TrAAm Atlanta Harfsfield International Ailport - The APM System at Atlanta Hartsfield International Airport was the first deployment of a pinched loop APM cunfguration. While operational switching had been utilized previously at DFW, the Atlanta system was the first to utilize switching with the coordinated reversing movements at end stations to allow two parallel linear guideways to accommodate a loop mode of operation. This configuration and mode of operation was a very important contribution to the APM industry. In many APM applications, the objective is to connect two separated locations (e.g., airport terminals) with transportation service. Thus, a linear guideway configuration is an obvious choice. However, unless the two locations are

48 Dennis M. Elliott and Jack Norton reasonably close together, a shuttle configuration often cannot provide sufficient capacity because of the time required in transit.

14 48 Dennis M. Elliott and Jack Norton reasonably close together, a shuttle configuration often cannot provide sufficient capacity because of the time required in transit. In these instances, a pinched loop mode allows for the desired linear guideway codiguration, combined with a loop mode of operation, which provides the required system capacity and frequency of service. Other Noteworthy Svstems New Tokyo International Airport - The APM shuttle system operating at Tokyo's Narita International Airport is unique because it is the first cable-propelled APM system installed at an airport. In addition, this system features Otis Transit Systems' patented air suspension technology. At Narita, the vehicles are suspended on a thin (3/4") cushion of air emanating fiom a number of circular air pads under the vehicle. Thus suspended, the vehicles are propelled by attached cables, driven by cable-drive systems located at the end of each guideway. Since this first installation, other installations have been made at the Cincinnatmorthern Kentucky International Airport, and non-airport locations. Because of its competitive pricing structure, and because many airports require shuttle systems for easy expansion, this technology may see more widespread use in future airport APM systems. George Bush Intercontinental AirprUHouston - The "tunnel train" at Houston's George Bush Intercontinental Airport is unique because it is the first (and to date, only) deployment of Bombardier's WEDway technology. First developed by the Walt Disney Company for use in its theme parks, the WEDway system uses passive vehicles propelled by linear induction motors mounted in the guideway. Since the vehicles operate in an air-conditioned tunnel, no on-board equipment of any kind is used. Even the door openings and closings are performed by wayside actuators. Newark International Airport - Opened in 1996, the Newark Airport Monorail represents the first installation of a free-standing monorail system at an airport. The Newark Monorail system is unique in that its trains are supported and guided by an elevated mono-beam guideway. While persons not familiar with APM systems often refer to them generically (and incorrectly) as "monorail systems," the Newark technology is in fact a monorail, because the vehicles actually "straddle" the supporting structure.

15 An Introduction to Airport APMSystems 49 Conclusion Currently, the APM industry is enjoying robust health. There are many systems in construction, design, and planning. Summarixing the current activities, it appears that there are four major trends that are shaping the industry: (1) Continued application of APM systems at large airports; (2) refiubishment of older existing APM systems; (3) deployment of APM systems at smaller airports; and (3) construction of off-airport APM systems for airport access purposes. Continued application of APM systems at large airports - At this writing, there are a number of substantial APM systems either in construction, design andor planning at major airports throughout the world. Examples include: Hong Kong; Dallas/Fort Worth (a new system to replace the Airport Train); San Francisco; Kuala Lumpur (Malaysia); Houston Intercontinental (a new system); Las Vegas (a new system); Paris (Charles de Gaulle); Los Angeles; Miami; Minneapolis-St. Paul; Seoul; and Singapore. It is likely that this trend will continue, driven by the relentless increase of air passengers, and the likelihood of even larger aircraft in future years. Refurbishment of older existing APM systems - Another significant trend in the APM indusby is the "recycling" of the oldest systems; either by refiubishment or replacement. Dallas/Fort Worth has undergone significant refurbishment and upgrading; as part of the TrAAm project, all of the on-board vehicle electronics were replaced, as were all of the vehicle bodies. In Tampa, the origmal vehicles have been replaced with new CX- 100 vehicles. Similarly, at Seattle-Tacoma, a project is underway to replace the original vehicles and train control equipment, and refurbish the tunnel structures and stations. Orlando is also in the midst of a vehicle replacement program. This trend is not surprising, considering that the oldest APM systems have been in operation for almost thirty years. It is reasonable to expect that this trend will accelerate, as more APM systems reach the ends of their useful lives. Deployment OfAPMsystems at smaller airports - As mentioned earlier, new APM technologies are now available at somewhat lower cost than before. This development bodes well for another industry trend -- the deployment of APM's at smaller airports, where conveyance systems are

50 Dennis M. Elliott and Jack Norton needed between terminal components, or to parking garage(s), but the level of passenger traffic does not warrant the expense of a large-scale system.

16 50 Dennis M. Elliott and Jack Norton needed between terminal components, or to parking garage(s), but the level of passenger traffic does not warrant the expense of a large-scale system. Many airports could use an APM system, if they could af ord one. It now appears that a market for lower-cost APM's is emerging. This trend will almost undoubtedly continue, and expand, in the future. Constmdion of off-airport APM systems for airport access purposes - Within the past year, a significant decision by the U.S. Department of Transportation has paved the way for a new type of APM system -- the off-airport system. An important source of funding for airport APM systems in the United States is the revenue derived from the Passenger Facility Charge (PFC) that many airports levy on airport passengers using their facilities. These revenues have previously been applicable to only on-airport development, including APM systems. However, the US DOT has recently allowed the Port Authority of New York and New Jersey to apply PFC funds to an APM system that will operate at Kennedy International Airport. In addition to serving inter-terminal passengers at the airport, the new APM will extend off of airport property to interface with New York Transit Authority lines. This connection will provide New York air passengers with the opportunity to travel to and from the airport entirely on fixed-guideway public transit. Assuming that the US DOT will apply this policy to other airports besides Kennedy in the future, it seems certain that this trend of off-airport APM's will continue in the fhture. Based on the above trends, it seems a safe prediction that the airport APM industry will continue to grow in the hture. In so doing, it will provide an ever-increasing benefit to millions of air travelers throughout the world.

Airport Characteristics. Airport Characteristics

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