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From page 59... ... SECTION 12 59 Case Studies 12.1 Port Authority of New York & New Jersey, AirTrain JFK Case Study 12.1.1 AirTrain JFK The AirTrain, operating at John F. Kennedy International Airport (JFK) , in New York City, is an 8.1‐mile (13 km) Read the entire page →
From page 60... ... SECTION 12 – CASE STUDIES 60 communications components very difficult; however, their installation and maintenance can be very challenging. In general, inductive loops have limited data communications capacity, and any information other than signaling data cannot be easily added, unlike more recent CBTC projects. At the core of the carborne equipment is the Vehicle Onboard Controller (VOBC) . Each car is equipped with one VOBC and antennas which serve as a communications interface to wayside loops. Each VOBC has a dual Control Processing Unit (CPU) Read the entire page →
From page 61... ... SECTION 12 – CASE STUDIES 61 mph. Given that there are no wayside signals, the driver relies on switch position indicators to confirm switch position. However, when a failed VOBC can be successfully recovered, the affected train must be manually reentered into ATC by manual driving over "entry points" (loop boundaries) . During the early stages of CBTC deployment, AirTrain JFK had experienced a few onboard controller failures which made the train unable to operate in CBTC mode, but over the years many issues and software bugs have been ironed out, which in the end led to improved overall performance and only a few onboard controller failures per year. VCC functional failures, however, result in a system‐wide halt, and trains cannot be moved until the VCC is recovered. If none of the trains were moved (manually recovered) Read the entire page →
From page 62... ... SECTION 12 – CASE STUDIES 62 12.1.10 Future Projects AirTrain JFK does not have any plans to add any secondary train detection and protection system. In terms of general system performance, AirTrain JFK has incorporated numerous enhancements to its originally deployed CBTC to improve revenue service and optimize the maintenance efforts. 12.1.11 Conclusion Key takeaways from this greenfield driverless airport link case study are summarized below. 1. No secondary detection and protection system. Read the entire page →
From page 63... ... SECTION 12 – CASE STUDIES 63 With successive expansions in 1990, 1994, 2002, and 2016, the agency nearly tripled its original network size to what is now a system of 39 stations and 44 miles (70 km) of revenue track linking downtown Vancouver to the region's northeast and south municipalities, using dedicated right‐of‐way made up of bridges, tunnels, at grade, and mainly elevated corridors. Today, SkyTrain provides service to 250,000 daily riders on the Expo, Millennium, and Evergreen Lines using a fleet of three different car generations totaling 340 CBTC equipped vehicles. These trains can operate in configurations of two‐, four‐, or six‐car trains, are capable of automatic coupling/uncoupling (among same car class) Read the entire page →
From page 64... ... SECTION 12 – CASE STUDIES 64 The contract between provincial and local government representatives and UTDC was signed in 1981 to build Phase I. After two years of planning and engineering, the construction of the system started in 1983 and finished by early 1986, six months ahead of the Expo 86 timetable. The Expo Line was commissioned and approved for revenue service in late 1986, making it the third driverless greenfield CBTC rapid transit system after Scarborough, ON, and Detroit, MI in North America. • Award date: December 1981 • First revenue service date: 1986 • ATO operation, driverless • CBTC coverage in the yard • CBTC inductive coupling provides communications between wayside and carborne • Secondary system: none Phase II, featuring an expansion of 1.9 miles (3.1 km) , was completed in early 1990, followed with Phase III's addition of 2.7 miles (4.3 km) Read the entire page →
From page 65... ... SECTION 12 – CASE STUDIES 65 phase shift in the signal at each loop crossover. Using onboard antennas, the carborne equipment detects the crossovers and counts them. The information, when combined with odometry signals generated by axle‐mounted tachometers, provides a safe, highly accurate train position measurement. The system uses a moving block train separation principle to keep trains at a safe distance. Portions of track reserved for a single train are adjusted in very small units and are updated as frequently as once per second. Unlike a conventional fixed‐block system, the minimum spacing is speed dependent, with fast moving trains given more stopping room than slow moving trains. This allows maximum capacity while ensuring safety throughout the system. The wayside control is in continuous communication with all trains in all territories. The Vehicle Control Center (VCC) receives position information from each train and calculates the allowed speed and safe stopping points between consecutive trains. Moving trains are therefore constrained to stay within their envelope defined by the speed, braking rate, and available space, so that they do not exceed their respective safe stopping points. Depending on the severity of communications loss between the wayside and carborne controllers, the ATC enforces appropriate fail‐ safe states, i.e. command emergency braking to non‐communicating trains, temporary speed reduction to indirectly affected but otherwise communicating trains, or halt all trains until the issue is resolved. 12.2.5 Secondary Train Detection and Protection Systems SkyTrain's network does not have a secondary detection or protection system nor any conventional signals on the wayside. 12.2.6 Feedback on the Deployment The original SkyTrain Expo Line and ensuing expansions are greenfield CBTC projects which had both wayside and carborne CBTC deployed at the same time. One of SkyTrain's keys to success was that its construction schedule was carefully planned from the start by transit professionals, not by contractors or vendors. This management allowed ensuing work to proceed with minimum delays. When an unforeseen issue developed during the deployment, the alternatives were carefully evaluated and implemented. In late 2016, SkyTrain added 28 new third generation four‐car trains to alleviate capacity needs on the Expo and Millennium Lines. The cars were delivered in time for the opening of the Evergreen extension to the Millennium Line, featuring 6.8 miles (11 km) Read the entire page →
From page 66... ... SECTION 12 – CASE STUDIES 66 Over the years, it was found that one of the most severe disruptions to CBTC communications were those related to intermittent ground faults (arcing) on traction motors. Though infrequent, such events can generate powerful local electromagnetic interference (EMI) Read the entire page →
From page 67... ... SECTION 12 – CASE STUDIES 67 repairs. The manually driven work cars get access to the mainline after the last revenue train has left service. Though strictly presented as an abstract, SkyTrain has evaluated an idea of using a frequency jammer fitted to a work car which could be used near the work zone boundaries to jam CBTC communications and inhibit the operations of CBTC trains within the work zone, in case work trains need to go on the mainline during regular service. SkyTrain does not intend to incorporate any form of CBTC to work trains, even a degraded CBTC version for tracking purposes. 12.2.9 Feedback Regarding the Broken Rail Issue SkyTrain uses a local inspection company experienced in general Non‐Destructive Testing (NDT) methods to inspect its running rails. The contractor utilizes a custom built, slow moving push cart to perform ultrasonic inspection of running rail at regularly scheduled intervals every 24 months. In case of unclear or incomplete readings, technicians will recheck questionable areas using the hand scanners. Over the last 30 years of operations, SkyTrain has had an extremely low count of running rail problems. One of the reasons is that system uses light axle loads on 115‐pound rail. Historically, there was one incident of broken rail and three cases of serious cracks. The sole broken rail incident occurred early in the fourth year of the system's operation during a harsh winter; the fracture took place next to a thermite weld. Ensuing investigation attributed the incident to rail being laid too hot and forces pulling the rail apart (shown by the completely vertical brittle‐looking fracture) Read the entire page →
From page 68... ... SECTION 12 – CASE STUDIES 68 made it more reliable and flexible. Additional specific changes are being planned to make the system more robust and service SkyTrain's specific operating needs. An STD/PS was not part of the original technical specification nor ever considered subsequently. Given the system's high redundancy scheme and maintenance access to track during nightly off hours, it can be asserted that STD/PS would not bring much value for the investment, if any. 12.3 New York City Transit Case Study, Canarsie and Flushing Lines 12.3.1 New York City Transit The New York City Transit (NYCT) Subway is a heavy‐rail rapid transit system, connecting four New York City boroughs ̶ Manhattan, Brooklyn, Queens, and the Bronx. NYCT Subway is a subsidiary of the state‐ run Metropolitan Transportation Authority (MTA) Read the entire page →
From page 69... ... SECTION 12 – CASE STUDIES 69 strategy, NYCT shortlisted well‐established signaling suppliers, and asked for a demonstration of their respective CBTC technologies on a designated test track. The results of these trial tests were later used to determine technical and project management proposals, and to conduct system safety audits, as part of the efforts to select the most appropriate CBTC technology for NYCT. In December 1999, the CBTC signaling contract was awarded to several contractors, who formed a "CBTC Joint Venture" to design, furnish, install, test, and commission the system. Installing the new system meant mounting radio transmitters on the trains, and wayside. The Canarsie Line CBTC architecture incorporates an STD/PS. The deployment of CBTC was coordinated with procurement of R‐143 cars, which were delivered as CBTC‐ready cars, but had entered revenue service approximately one year before the CBTC equipment was delivered and installed. This CBTC "readiness" involved the provision of space, mounting brackets, power capacity, wiring, and cables. By the end of the project, an additional 20 R‐160 four‐car train units were also equipped with CBTC. Currently, the service on the Canarsie Line is supported by 59 CBTC equipped train units. The Canarsie Line's CBTC system was commissioned and approved for revenue service by late 2006, making it the first brownfield CBTC project to be deployed on a North American mass transit system. Canarsie Line's quick facts: • Award date: December 1999 • First revenue service date: 2006 • Last revenue in‐service date: 2010 • Secondary Detection Method: track circuits The modernization of the Flushing Line started in November 2012 and, at the time of writing this report, the anticipated completion date is planned for the second quarter of 2017. The Flushing Line (7) provides both local and express service (express service only during peak hours and in peak direction) Read the entire page →
From page 70... ... SECTION 12 – CASE STUDIES 70 several (degraded) operating modes available for operations that include handling of CBTC subsystem failures. When in Yard mode, for example, the CBTC enforces safe operation through power‐operated track switches installed throughout the Canarsie and Corona yards. When traveling within CBTC territory under failure conditions, the CBTC equipped trains can be moved and operated using conventional wayside signaling, with the onboard CBTC equipment set to one of the degraded operating modes, thereby minimizing the adverse impacts on the line's service. Though equipped by two different CBTC suppliers, both Canarsie and Flushing CBTC systems feature the following: • ATO and manual operation under CBTC supervision are possible • CBTC coverage in the yard • Brownfield projects (CBTC added to wayside signaling which remains as STD/PS) Read the entire page →
From page 71... ... SECTION 12 – CASE STUDIES 71 The Canarsie and Flushing Lines feature relay‐based interlockings, with few exceptions for processor‐ based interlockings. Most the interlockings were renewed and brought up to NYCT CBTC standards before the deployment of the actual CBTC project. 12.3.5 Feedback on the Deployment Deployment of the Canarsie CBTC involved various intermediate steps. In general, the details of the migration plan evolved as the project progressed, but the overall core cut‐over strategy has remained intact: the legacy and new systems needed to work together during the intermediate stages, in which the non‐equipped trains would progressively transition into the CBTC equipped fleet, and until such time when the new control system would be able to take control over the line. Disruptions to passenger service during the installation, testing, commissioning, and early service operation of the new system were to be kept to a minimum. To achieve this, the legacy track circuit system had to be retained to ensure train detection and protection for both non‐equipped and CBTC equipped trains. Hence, existing signals, and in some cases the addition of new ones, were used to facilitate the deployment. Eventually, signals and other assets used to support the cut‐over phases were removed. The approach allowed integration of CBTC on a per‐section basis and allowed mixed‐mode operation until gradually all trains were CBTC operational. This approach also involved an option to isolate CBTC from the relay‐based interlockings. For example, the Zone Controller outputs were disconnected in the relay room until CBTC was commissioned. For testing purposes, the specific Zone Controller outputs could be connected to validate and stress the system. NYCT's Zone Controller outputs are grouped on a per‐track basis, so that individual tracks can be tested, thereby minimizing impact on passenger service. As the Canarsie Line's CBTC was capable of mixed‐mode operation, the deployment and equipping of the new R‐143 cars was handled in gradual steps. Not all trains serving the line were equipped prior to the start of CBTC operation. Additionally, to standardize future CBTC carborne interfaces, the R‐143 carbuilder and all potential CBTC suppliers had to set and agree upon carborne CBTC interfaces that could accommodate use of CBTC equipment from any of the CBTC suppliers. In the end, the main differences in the system architecture between the CBTC suppliers was in the number and the type of positioning/odometry sensors, i.e. tachometers, speed sensors, Doppler radars, transponder interrogator antennas, etc. 12.3.6 Feedback on Operation Wayside Zone Controllers are installed in technical rooms along the route, and feature full redundancy with overlapping coverage to help mitigate failures. In the event of double Zone Controller failures, i.e. complete loss of redundancy, the system is designed to default to STD/PS. In case of double Zone Controller failures on the Canarsie Line north of Broadway Junction for example, the system would switch over to an absolute block protection with no more than one train per interstation. Whereas in case of failures south of Broadway Junction, the system would switch over to STD/PS, and train movement would resume under the secondary train control protection. Double Zone Controller failures on the Flushing Line are handled by switching to STD/PS. In general, double Zone Controller failures are an extremely rare occurrence. The NYCT CBTC system features a specific function which is used to mitigate the impact of secondary system failures to the CBTC operation. This function is called Restricted Authority (RA) . In case of failures involving track circuits, signals, or train stops, or in case the status of equipment becomes unavailable to the CBTC system, the ATS operator at the control center can issue the RA command which allows CBTC trains to continue operation over the failed equipment. Trains operating under RA can only be operated in manual mode under CBTC supervision and can only move at restricted speed over the affected area. Read the entire page →
From page 72... ... SECTION 12 – CASE STUDIES 72 Another NYCT‐specific feature is civil speed protection used to handle cases of communications loss between carborne and wayside Zone Controller, or complete Zone Controller failure but otherwise healthy Carborne Controller (i.e. train localization is valid) . Though an extremely low probability event, under such circumstances, the system can operate using the STD/PS with full civil speed protection enforced by carborne CBTC. Onboard Communications Units are installed on each train car and feature full redundancy. In the event of double Carbone Controller failures, the system drops out of CBTC and applies the emergency brakes. Though a rare occurrence, a train with CBTC failure which cannot be restored back to CBTC is switched over to Restricted Manual mode, under which train speed is limited to 10 mph, or to bypass mode which has no speed limitation. The affected train can then be moved under STD/PS. There are, however, frequent cases where CBTC issues or operational events result in an emergency brake application, but following a quick recovery procedure, the train can resume operating in CBTC. 12.3.7 Feedback on Maintenance Fleet The NYCT work cars are not equipped with CBTC, and their movement on the CBTC equipped lines is handled by STD/PS. As part of the long term planning, NYCT Subway intends to incorporate a degraded version of CBTC tracking of work trains. Currently, defining the length of the work train is the single largest problem as NYCT utilizes different train lengths. Two out of four Track Geometry Cars (TGC) Read the entire page →
From page 73... ... SECTION 12 – CASE STUDIES 73 4. On the Canarsie Line, the STD/PS is capable of supporting operation of non‐equipped trains (running in degraded service) Read the entire page →
From page 74... ... SECTION 12 – CASE STUDIES 74 PATH project summary: • Award date: December 2009 • First revenue service date: Expected in 2017 • Entire Line under CBTC: Expected in 2018 • Secondary detection system: track circuits • Secondary protection system: signals with overlapping control lines and train stops to enforce signals, implemented with processor‐based interlockings integrated with CBTC • Signaling system supplier: Siemens Mobility 12.4.3 Legacy System The legacy system is based on fixed‐block wayside signals enforced by mechanical train stops. Train detection is achieved using track circuits. Several types of signals are used to govern interlockings, provide train separation and enforce train speed at certain locations through timer logic. All switch machines and train stops are electro‐pneumatic. All vital circuits are relay‐based, except those between the World Trade Center and Exchange Place. These were changed to processor‐based circuits after the September 11, 2001 attacks on the World Trade Center station caused severe damage to that portion of the system. Non‐vital circuits are a mix of relays and processors. The performance of the legacy signaling system can meet the current demands with trains as close as 2 minutes apart. Traction power is supplied by a covered third rail at a nominal 650 VDC. Track circuits use alternating current and operate at various power frequencies: 25 Hz in the tunnel portion using the original Hudson & Manhattan Railroad 25 Hz signal power distribution system; 60 Hz for newer installations; and 91‐2/3 Hz in the outdoor portion to avoid harmonic interference from the adjacent Northeast Corridor. Most track circuits are of the double‐rail type with impedance bonds. 12.4.4 Secondary Train Detection and Protection Systems PATH has selected the new signaling system with a full STD/PS capable of off‐peak revenue service on the entire system in both directions. The secondary detection and protection system uses track circuits and wayside signals, which are present at interlockings and in between interlockings for train separation. Two different types of track circuits are used: jointless audio frequency (AF) track circuits and power frequency (PF) Read the entire page →
From page 75... ... SECTION 12 – CASE STUDIES 75 The deployment is being made section by section on the network. On the first section, almost all signals were kept to mitigate early CBTC failures. However, on other sections, some signals were removed. Equipment for all trains will be installed before commissioning the first section. 12.4.6 Feedback on Operation At the time of the case study, CBTC operation in revenue service has not started yet. However, STD/PS in the first section is in service without CBTC. CBTC operation will be possible in automatic mode and in manual mode under CBTC supervision. Both the Train Engineer and the Train Conductor will remain on board the train after deployment of CBTC. The main yard is partially equipped with CBTC. The signaling system for most of the yard is a conventional signaling system using track circuits as the method of train detection. The secondary system will be used to track trains with CBTC failure and work trains. Detection will be made by track circuits and the wayside signals will be able to maintain a headway compatible with off‐ peak revenue service. PATH will continue to operate 24/7 with about a 30‐minute headway at night. The maintenance is done mostly while single‐tracking during off‐peak hours. 12.4.7 Feedback Regarding the Broken Rail Issue Because of the reasons mentioned above, including being under the jurisdiction of the FRA, PATH selected track circuits as a secondary detection system and primary active method to detect broken rails. PATH also performs a daily visual inspection of the tracks and has recently acquired an ultrasonic inspection vehicle and handheld devices. 12.4.8 Conclusion Key takeaways from this case study: 1. Decision to implement a full STD/PS was based in part on the availability concerns related to a "new to the United States" technology. Read the entire page →
From page 76... ... SECTION 12 – CASE STUDIES 76 12.5 Transport for London Case Study, CBTC 12.5.1 Transport for London Transport for London (TfL) is an integrated transit authority for London, UK, responsible for managing major aspects of Greater London's transportation systems. The TfL's operational responsibilities include all major surface and underground transit operations involving London Overground, London Trams, Docklands Light Railway, London Underground and TfL Rail. TfL is one of the largest and busiest transit authorities in the world, delivering 31 million journeys on an average day, with an annual ridership close to 1.5 billion passengers. To accommodate growing passenger demands and achieve significant increase in train running capacity, the TfL rail lines required a significant overhaul and upgrades to its signaling system. CBTC was first deployed on the Docklands Light Railway, followed by London Underground's Jubilee and Northern Lines. Most recently, the Victoria Line has been converted to CBTC (different technology and supplier to that of its predecessor) Read the entire page →
From page 77... ... SECTION 12 – CASE STUDIES 77 • Secondary detection system: axle counters • Signaling system supplier: Thales Transportation Solutions 12.5.3 Legacy System Prior to CBTC, both the Jubilee and Northern Lines were using conventional signaling systems with track circuits used for detection and train stops used for signal enforcement. The trains were operated in manual mode under wayside signal authority. Operations with conventional wayside signals were similar to U.S. transit agencies such as NYCT or the Massachusetts Bay Transportation Authority. 12.5.4 Secondary Train Detection and Protection Systems For both these projects, the secondary detection system to support the CBTC implementation was based on axle counters. On prior projects, TfL had gained experience with axle counters deployed in one depot but not on mainline tracks. Axle counters are common in the UK; Dockland Light Rail and Network Rail used axle counters on their signaling projects. Axle counters are used primarily for: 1. Failure management: The line cannot be operated in revenue service without CBTC, i.e. with the axle counters only. Axle counters are used to track trains with CBTC failure. Operation of trains with CBTC failure is limited to 10 mph and line‐of‐sight since there are no signals on the wayside. Read the entire page →
From page 78... ... SECTION 12 – CASE STUDIES 78 operating on non‐CBTC sections. This method required a manual transition on board the train when going from one system to the other. Before CBTC operation started on the first section, the entire fleet of trains was equipped with CBTC. There was no need for mixed‐mode operation where one CBTC train runs among other non‐CBTC trains. Regarding installation, TfL indicated that axle counters were susceptible to electromagnetic interference generated by the traction power system. TfL uses a third‐ and fourth‐rail system to power the train, along with traction power and negative return cables. Therefore, locations of axle counters and the layout of their cables in the field must be carefully planned with the traction power system. Also, to allow maintenance of the axle counters to be performed safely, the third rail must not impede on the space around the axle counter. The success of the CBTC projects was made possible with a robust test strategy along with a recovery plan during the deployment of the system. 12.5.6 Feedback on Operation TfL operates CBTC trains in ATO mode where the driver starts the train after each stop. Yards are not equipped with the new signaling system and manual line‐of‐sight operation is used in these areas. Non‐CBTC equipped work trains are not permitted during revenue service. When a non‐CBTC equipped work train is used, it operates within a dedicated area. Trains with CBTC failure are operated at slow speed using line‐of‐sight. There are no signals on the wayside. Revenue service is not possible without the CBTC system. Axle counters are used to track trains with CBTC failure and only the train with CBTC failure is authorized to move in the area. TfL indicated that there were very few wayside failures since the beginning of revenue service of CBTC. The Jubilee Line has five wayside controllers and the Northern Line has eight wayside controllers. In US projects, wayside controller Mean Time Between Functional Failures are usually specified for about 100,000 hours, and based on discussion with TfL, the system put in place in London meets this requirement. When a wayside controller failure occurs, all trains in the area controlled by this controller are forced to stop. Rebooting a wayside controller only takes about 10 minutes and therefore these failures can be fixed quickly without causing major delays. Wayside controllers have a 2‐out‐of‐3 architecture; if a failure on one computer occurs then the wayside controller continues operation with a 2‐out‐of‐2 architecture until further maintenance can be performed at night when there is no passenger service. 12.5.7 Feedback Regarding the Broken Rail Issue Detecting a broken rail after it happens using a track circuit is too late because it dramatically impacts train operation. It is important to prevent broken rails from happening to avoid such delays. In addition, based on TfL's own experience, track circuits are an inefficient method to detect broken rails. One reason cited was that a broken rail often happens when a train runs over the area and, since axles of the trains are shunting the rails, it is not possible to detect and slow down the train when passing over the broken rail. In addition to visual inspection, TfL is using ultrasonic inspection and a longitudinal rail stress measurement program. The program is the same on all TfL lines, whether the signaling system includes track circuits or not. The rail issue detection program put in place is efficient and did not need to be optimized since introduced. Inspections are performed mostly at night; however, some of the revenue service trains are equipped with ultrasonic inspection and other rail issue detection equipment. The data from these trains is only available when the train comes to the yard, but since inspections have the capability to detect rail flaws before the rail break, this is not an issue. Read the entire page →
From page 79... ... SECTION 12 – CASE STUDIES 79 12.5.8 Conclusion Key takeaways from this case study: 1. Secondary detection system is based on axle counters. No wayside signals are present. Read the entire page →
From page 80... ... SECTION 12 – CASE STUDIES 80 12.6.3 Legacy System The mainline signal system consists of AF‐400 track circuits and a cab signaling system supplied by Union Switch and Signal. There are more than 400 track circuits that provide detection throughout mainline and yard track. The yard, however, is not included in the AF‐400 system and is provided with power frequency (PF) track circuits throughout. The yard accommodates only manual movement of trains, where the trains are limited to 12 mph with an onboard generated cab signal code, when the operator places the mode selector switch to the yard position. The train control equipment is distributed along the mainline and yard among 17 train control rooms that include the audio frequency track circuit racks, the power frequency racks for the 8 mainline interlockings, and relay racks for occupancy status in the yard. The wayside network connects the train control rooms to central control as well as to a back‐up control facility located in the yard tower. 12.6.4 Replacement CBTC System The CBTC replacement solution will materialize in response to the performance requirements identified in the Request for Proposal (RFP) Read the entire page →
From page 81... ... SECTION 12 – CASE STUDIES 81 Administration has included options for flawed rail detection in the Railcar and Train Control Contract. Although the track circuit approach is limited to only indicate complete rail breaks, it is one of the options permitted. The second option described in the RFP is the provision of a high‐rail vehicle capable of not only inspecting the running rails of the Metro system using ultrasonic techniques, but also capable of the same inspection performance on the Maryland Transit Administration light rail system. For the Maryland Transit Administration, requiring the high‐rail alternative to also accommodate the needs of their light rail provides more utility from a valuable piece of railroad equipment. 12.6.7 Conclusion As the Baltimore Metro system replacement is in the procurement stage, the implementation of CBTC, STD/PS, and rail flaw detection have not been decided yet. With a winning bid and with a notice to proceed the technical specifics of the contractor's proposal will begin to be finalized as part of the design review process. Nonetheless, the Maryland Transit Administration has concluded: 1. The desire to continue to track Maintenance‐of‐Way work trains (non‐communicating) Read the entire page →

From page 59...

... SECTION 12 59 Case Studies 12.1 Port Authority of New York & New Jersey, AirTrain JFK Case Study 12.1.1 AirTrain JFK The AirTrain, operating at John F. Kennedy International Airport (JFK) , in New York City, is an 8.1‐mile (13 km)