National Academies Press: OpenBook
« Previous: Chapter 4 - Shared-Track: A Handbook of Examples and Applications
Page 77
Suggested Citation:"Chapter 5 - Shared Use: Progress and Evolution." National Academies of Sciences, Engineering, and Medicine. 2009. Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/14220.
×
Page 77
Page 78
Suggested Citation:"Chapter 5 - Shared Use: Progress and Evolution." National Academies of Sciences, Engineering, and Medicine. 2009. Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/14220.
×
Page 78
Page 79
Suggested Citation:"Chapter 5 - Shared Use: Progress and Evolution." National Academies of Sciences, Engineering, and Medicine. 2009. Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/14220.
×
Page 79
Page 80
Suggested Citation:"Chapter 5 - Shared Use: Progress and Evolution." National Academies of Sciences, Engineering, and Medicine. 2009. Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/14220.
×
Page 80
Page 81
Suggested Citation:"Chapter 5 - Shared Use: Progress and Evolution." National Academies of Sciences, Engineering, and Medicine. 2009. Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/14220.
×
Page 81
Page 82
Suggested Citation:"Chapter 5 - Shared Use: Progress and Evolution." National Academies of Sciences, Engineering, and Medicine. 2009. Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/14220.
×
Page 82
Page 83
Suggested Citation:"Chapter 5 - Shared Use: Progress and Evolution." National Academies of Sciences, Engineering, and Medicine. 2009. Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/14220.
×
Page 83
Page 84
Suggested Citation:"Chapter 5 - Shared Use: Progress and Evolution." National Academies of Sciences, Engineering, and Medicine. 2009. Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide. Washington, DC: The National Academies Press. doi: 10.17226/14220.
×
Page 84

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Given the preceding information, what means are available to advance this concept to true shared use of track? A few operations are on the verge of crossing the threshold, but that first step has yet to be taken. • What actions are most likely to impel the process? • Will a demonstration project help? • Will the advantages outweigh the disadvantages? • What are the barriers to progress? Up until now, this concept has been equated with a “leap into the unknown” for all stakehold- ers, especially policy makers, planners, and regulators. Yet achievements to date are indicative of the benefits and future opportunities. Demonstration Project A viable business case for shared-track can be made and results from the risk analysis model indicate that equivalent safety criteria can be met. Widespread consensus exists in the transit professional community on the next steps for the shared use of track by conventional railroad trains and light passenger rail cars. With the background research on signaling, communica- tions, operating methods, and vehicle technologies presented in Chapter 2 (detailed in the reports for Tasks 1 through 4), and business model and national business case information pre- sented in Chapters 2 and 4 (detailed in the reports for Tasks 7 through 10), a clear picture for the way forward has emerged. Determination of project feasibility parallels that of making the viable business case. In particular, the planning process requires four main steps, described in Chapter 2 (detailed in the Task 9 report): (1) Identify Service Requirements; (2) Define Alternatives; (3) Choose Shared-Track Operating Regime; and (4) Complete Economic Analysis. This process (or a stan- dard alternative analysis process) should be followed to determine project feasibility and to under- stand demonstration project opportunities and constraints. In the case of an existing system, this process is less arduous, because it has already established a track record of safety as evidence for regulators. At the present time, a demonstration project for shared-track operations may take one of two possible forms: 1. A currently operational, temporally separated shared-track line has identified a business need that requires concurrent operations; or 2. A currently operational light rail system has demonstrated a need to extend or expand its sys- tem using an adjacent freight railroad branch line. 77 C H A P T E R 5 Shared Use: Progress and Evolution

Collision Safety of the Demonstration Project Project sponsors will have the burden of proof to satisfy the FRA that equivalent safety would be achieved by the chosen technology and operating methods. The project team has identified three key issues related to federal regulatory acceptance for a concurrent shared-track demon- stration project. 1. Understanding the severity of consequences of collisions between a light passenger rail car and conventional freight equipment through structural analysis. The result of collision may not be catastrophic. 2. Understanding differences in the rail-highway grade crossing risks posed by comparatively lighter rail vehicles. The grade crossing collision risks should be appropriately managed with due consideration to the speed of light rail cars, braking capabilities, and the type of traffic crossing over the railroad. 3. Demonstrating a consolidated equivalent level of safety in all aspects of the proposed opera- tions. A risk analysis (safety case) specific to the line, demonstrating that the combination of train control system and other mitigation measures makes the system at least as safe as a stand alone light rail line or a conventional commuter rail line. These issues are valid concerns to be addressed in a waiver petition for demonstration or pilot operation of concurrent shared-track. However, the transit system should not be held to a higher standard than other modes, and the null alternative—risks if nothing is done—needs to be considered. Collisions Between Light Passenger Rail Cars and Conventional Equipment The severity of collisions is the leading safety concern with concurrent shared-track opera- tions. Many options are available to reduce the frequency of train-train and intrusion collisions, but the risk cannot be entirely eliminated. Much less information about the severity of conse- quences is available. Because the practice is relatively new and because measures to reduce the likelihood of collisions have been very effective, no meaningful historical accident information exists. If current and planned preventive measures are successful it will remain that way. Only very simple analyses of hypothetical collisions have been performed. For the limited concurrent shared-track operations, such as the River LINE and San Diego Trolley, the FRA was provided with a qualitative risk assessment (performed by the transit agency) to provide safety assurance and took no exception to proposed train control systems and operating procedures for ensuring a fail-safe train separation. For more extensive concurrent operations, a more detailed analysis may be required. This analysis might include: • Formal three-dimensional structural crush and collision dynamics analyses of representative collision scenarios; and • A quantitative risk analysis that takes into account the results of the collision analysis and the expected performance of proposed train control systems. Application of Risk Analyses Methodology to the Demonstration Project The deficiencies of risk analyses are particularly apparent for concurrent shared-track proj- ects. There is little actual accident or incident data. All operations to date entail some form of temporal separation, and are not truly concurrent. Ironically, due to the excellent safety record of many rail transit systems, there is a dearth of transferable data for risk modeling purposes. An example of this lack of information can be seen in Europe where tram trains and other forms of commingled shared-track arrangements are more prevalent; accident experience with these types of operation are very meager. The risk model should reflect parameters considered appropriate to the shared-track envi- ronment. The analyses also should incorporate the impacts of actions that the prospective oper- 78 Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner’s Guide

ator of the shared-track demonstration can take to reduce risk. These parameters are summa- rized here. Recognized Risk Factors • Accident rate variability with volume and type of rail traffic. • Frequency, nature and proximity of freight traffic. • Single or double tracks, yard operations. • Operating speeds of the light passenger rail equipment. • Consider secondary collisions (effects on standees is a particular concern). • Reduced fire hazard from less fuel and improved protection for the fuel tank on typical DMU equipment. • The number of cars in the consist. • Collision effects on the articulated joint. • Collision effects on power module or propulsion components. • Number of grade crossings, volume and nature of highway traffic. Potential Risk Reduction Measures • Upgrade the track maintenance class to reduce the likelihood of a derailment. • Lower the operating speeds of freight. • Time of day track restrictions. • Add intrusion detection and other hazard detection devices. • Failsafe train separation. • Protection from freight siding roll-outs. • Automatic train protection. • Grade crossing warning system technology. • Extremely high braking rates and redundancy of brake system on DMUs and LRVs. • Well developed operating rules and procedures with training and enforcement program. • Provision of CEM design including frangible and crush-zone elements in vehicle, in addition to interior features that offer more impact attenuation for passengers. Ultimately, equivalent safety drives mitigation of risk. Risk reduction alternatives may involve federal compliance with negative cost or operational impacts, or adoption of systems that alle- viate specific hazards and reduce risk to levels consistent with those attained via regulatory com- pliance. To achieve a practical demonstration project of concurrent shared-track operations under the federal waiver paradigm: 1. Equivalent safety needs a precise and widely accepted definition that has an objective mean- ing to policymakers and technical staff; and 2. Risk mitigation measures should be quantifiable in the context of a shared-track environ- ment. These “adjustment” factors should be acceptable to a consensus of technical experts. Currently, risk assessment has been applied directly and exclusively to the rail mode, rather than comparing the results to other travel modes that would be used in absence of a shared-track system. Certainly planners and transportation specialists would like to know if relative risk increases or decreases, as a result of their plans. Further tests and demonstrations to gather technical information are critical for validation of risk assumptions, and provide experience in selecting systems, equipment, and operating prac- tices that contribute to a safe, concurrent shared-track environment. Data Collection Plan A demonstration project aims to achieve two goals: to explain the proposed technology to gov- ernment officials and the public at large and to collect data about the technology that will inform Shared Use: Progress and Evolution 79

the direction of technological research and development, and investment decision making. Any demonstration project should include a data collection plan and consider collecting an exten- sive set of cost and operating data. Key to the success of the demonstration project and for shared-track proponents in general is statistics confirming that risks to passengers in shared-track installations are no higher than a comparable conventional commuter rail system. In addition to the standard federal and state requirements on incident reporting, the demonstration project should collect statistics about inci- dents on shared-track lines with the goal of making a general safety case for this method of oper- ations in the future. Control center databases and vehicle event recorders can provide some of the raw data. Among the key events to record are: • Train control technology failures, including failsafe events and any events that do not fail safe or where some other active intervention is required to prevent an incident. • Incidents prevented (i.e., accidents averted) by the signal system. • Other near-misses where an incident was prevented by mechanisms other than the train con- trol system (and whether the incidents might have failed-safe had the other mechanism not functioned). • Standard statistics on passenger injuries, fatalities, and property damage if any accident should occur. Post-accident analysis of vehicles and systems should be carried out to identify any les- sons learned. • Grade crossing incidents, particularly actual vehicle strikes that result in railcar damage and grade crossing incidents where the enhanced braking rate of light rail vehicles is successful in preventing a collision, or instrumental in limiting injuries or damage. • Detailed operating statistics such as mileages and operating hours should be kept, such that accident rates could be normalized against any number of standard denominators. Suggestions for Demonstration Projects It is recommended that the shared-track transit systems currently operating in San Diego and Southern New Jersey be designated as demonstration systems for the development and promul- gation of the American approach to shared-track transit operations. The transit systems in the two cities represent two different approaches to the safe management of concurrent shared-track operations on opposite coasts of the nation. San Diego Trolley, Inc. The older San Diego system has developed a tightly scripted manual track warrant based approach to allow freight trains at the end of their diurnal period to operate on tracks connected and adjacent to tracks used by light rail cars at the start of the passenger service day. The system does not feature any technologies that ensure fail-safe train separation. The 25-year-old system ran concurrent freight and passenger operations successfully on shared track for the first decade of its operation before such practices were outlawed by federal regulation. Present investments in technologies and specialized infrastructure to ensure fail-safe train separation on the lines are modest. The organizational culture of the line is dominated by transit perspectives, in that San Diego Trolley is designed and operated as a traditional U.S. light rail transit system. Procedures and technologies for monitoring and controlling train movements do not strictly conform to standard U.S. railway operating practices. San Diego presents an opportunity to explore how existing shared-track systems can be upgraded with investments in technology and management systems to backstop the manual pro- cedures presently used for very limited concurrent operations. This should lead to the imple- mentation of management techniques and control systems that allow light rail and freight trains 80 Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner’s Guide

to use the shared tracks concurrently with a greater safety and frequency, thus improving service delivery for customers of both the freight and passenger railways. San Diego could be used as a test case for the framework proposed in Chapter 4 (the Task 9 report). The service goals and objectives would be formalized based on freight and transit service requirements. The aim is clearly to upgrade the system for full concurrent operations if required by the freight traffic densities and schedules. Different train control technologies would be eval- uated for the application, leading to installation and operation of a concurrent shared-track rail- way that fully meets the service requirements of both freight and passenger railway customers. NJ Transit River LINE New Jersey Transit’s River LINE opened decades after the San Diego Light Rail system and was specifically designed with frequent concurrent shared-track operations. In contrast to San Diego, the system features conventional train control technologies to ensure fail-safe train separation and was initiated with a conventional railroad rulebook and organizational culture to facilitate shared- track operation. The system is beginning to use a novel combination of Automatic Train Stop (for passenger trains) and interlocking controlled split point derails (for freight trains) to ensure fail- safe train separation between freight and passenger trains at locations where freight trains must cross or occupy short portions of the shared-track railway during the course of the normal pas- senger service day. NJ Transit’s unique combination of off-the-shelf transit and railway technolo- gies to ensure that only one class of train can occupy the shared-track at any moment in time may prove to be the key breakthrough that allows concurrent shared-track transit lines to be routinely designed, built, and operated on many urban or suburban low-density freight lines. The River LINE presents the opportunity to explore the incremental approach to improving the scope and technology of shared-track operations in a retro-fit fashion. It is a system of recent vintage designed with concurrent operations in mind but with only an incipient approach to controlling freight operations in the concurrent “fail-safe separation” mode of operation. Two years after the line opened, NJ Transit has committed to the NX signal logic (NX = entrance/exit) approach to locking out specific sections of shared-track to specific modes, recently adding approximately 2.5 miles territory to its NX zone. Other measures are being considered. The demonstration project should aim to understand the feasibility and scalability of the New Jersey approach over longer distances. NJ Transit and Conrail are interested in concurrent operations over longer lengths of the River LINE, particularly a 17-mile segment between Burlington and Trenton. Here the nature of the concurrent operation is more line-haul in nature rather than short crossing movements for which NX signal logic has been successfully applied. As a demon- stration system, NJ Transit would be encouraged to refine and document its promising approach to ensuring safety, while making efficient use of limited urban transportation assets available for the transport of passengers and freight. Barriers to Implementation This research has highlighted some of the advantages and disadvantages of the shared-track concept, even where near shared-tracks are currently practiced. None of the disadvantages is insurmountable, if shared-track is the right fit. Often, they can be overcome through technical, financial, or legal resolution. However, some more prominent barriers have subjective elements. These cases require alter- ations to the judgment of regulators or changes in the perspectives of policy makers. Since such perceptions can be based on the newness and limited experience with shared track and little expo- sure to DMU or LRV equipment, they need a stronger and more irrefutable objective argument to Shared Use: Progress and Evolution 81

overcome some preconceptions. More research and cumulative performance experience may be essential to effect a change. These impediments are the primary reason that the concept has not been more readily embraced, as evidenced by the number of transit agencies that opted for con- ventional rail systems and other projects that were simply stopped. • Liability: common to any passenger/freight operation (not unique to shared-track), but there is a lack of precedent and actuarial data for shared-track, so at the very least the unknown financial impacts may drive up the cost. • Safety issues: disparate speeds and operating weight, structural incompatibility in multiple dimensions, frontal configuration, service characteristics. • Waiver process: long, complex process; each is unique; may require external legal and techni- cal support at extra cost; invites external parties to evaluate project. • FRA Part 238 and 236 compliance (see waiver process): cost and legal implications. • Regulatory unfamiliarity: officials are unfamiliar with light passenger rail equipment, its per- formance capabilities and operations. More exposure to this technology and standardized vehicle design would aid understanding. • Risk analysis: application of risk analysis methodology and interpretation of results is some- what esoteric; validated data to quantify risk is lacking; modeling risk events is a complex affair; some have a natural inclination to dismiss risk concerns while others display a tendency to overstate them; one school of thought places excessive faith in risk management while another has insufficient faith. The probabilistic aspect does not satisfactorily address a “night- mare scenario” event. There is simply less comfort in calculating a one-in-a-billion chance of an accident event every 10 years. Regulators can more easily understand that if an accident occurs, then passengers are protected. • Lack of sufficient accident data: a perverse and ironic insufficiency of hard data compounded by lack of collision modeling via computer or field test results. • Rigid temporal separation: is a “zero-sum” game. If the one mode gains the other loses. • Potential for unknown outcomes: for planners, policy makers and all stakeholders, the planned or desired outcome of the effort is not assured. Costs, schedules, and technology choices are all subject to review and approval by the FRA, and may be amended at any stage in the process. • Lack of strong voice: the novel and niche role of shared-track needs strong local or state advo- cacy to support and encourage it. The participation of project champions and likely benefici- aries (e.g., shortline operators) should be solicited. • No corridor philosophy (similar to highway or air traffic): railroads are seen as exclusive cor- ridors for conforming equipment, not as corridors or highways available to different vehicles sharing the same route. • Local issues: particularly local speed restrictions for railroads enacted while plans are evolving can complicate or restrict the service plan; grade crossing impacts, associated horn-blowing noises, and ambient noise and operational impacts are also a concern. Shared Track—The Potential Market Track sharing between mainline trains and light passenger rail cars serves a niche market between commuter rail and a stand-alone light rail system. Viable operations in North America typically entail allowing a small number of branch line freight trains to operate over a line that is converted for medium-frequency light passenger rail use at limited speeds. The community will benefit or be impacted by the advantages or disadvantages arising from shared-track, which are summarized here. There is no implied weighting of these factors, they are simply identified. A transit agency and various stakeholders should assign the relative value (positive or negative) to each. 82 Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner’s Guide

Advantages • Increase accessible passenger market; public transportation available in new, less served areas. • Potential for route extensions, connections and passenger growth. Flexibility for test services. • Walkability to and from stations. • Downtown distribution. • Lower cost than light rail. • Quieter and with lower emissions than traditional commuter rail. • Induced growth may be economically beneficial to locality. • Shorter, faster trains. • Viable in edge cities and suburban neighborhoods. • Additional utilization of an existing railroad asset. • Reduced social disruption construction relocation, and environmental disturbance by using existing facility. Disadvantages • Conflicts with growth in freight traffic. Temporal separation can be a zero-sum game, with winners and losers. • Capacity limitations, not suitable for high density, high volume passenger movements. • Stations require parking and improved highway access, and generate traffic. • Noise generated by horn warnings when trains traverse grade crossings. • Increase in noisy freight movements that will likely shift to night. • A lightly used freight line must exist. The concept is applicable in selective circumstances. • Existing freight corridor may not be optimally placed to generate ridership. Growth may be induced where inappropriate or constrained by other factors. Ridership may be induced rather than mode shifted. • A cooperative freight partner is required. • Extended and complex bureaucratic process; success not assured. • Requires added systems and technology to protect passenger traffic from freight-based accidents. • Route will likely include a large number of grade crossings. Realistic or not, concern is increased with noncompliant vehicles. • Disparate speeds and weight, structural incompatibility of vehicles increases risk. • Each incremental change requires approval from the FRA. Market appeal can benefit from increased advocacy by state or local government entities and community movers and shakers as an economic stimulus and a practical approach to new sys- tem starts. Collaboration between a transit agency and a local shortline or branch line owner may be encouraged by explaining the potential infrastructure, economic, and operating advantages that would accrue. Shared-Track Operation—An Evolving Concept The future growth of shared-track operations is contingent upon shared-track being afford- able and achievable without sacrificing safety. Technical advances and evolution of a more sophisticated business case is likely to enhance shared-track’s appeal. The following recommen- dations for research and action will support progress for present operations and those being planned or considered: 1. Demonstration projects should encourage funding for development, evaluation, testing and documentation of methods to expand concurrent track sharing, and involve the SSO orga- nization too. In both California and New Jersey, it would include a detailed evaluation of what Shared Use: Progress and Evolution 83

types of concurrent operations are necessary and desirable. The demonstration would provide for development and evaluation of approaches to facilitate those operations. The demonstra- tion project would provide for design, deployment, testing, evaluation, and documenting, and recommend a preferred approach. Finally the project would report on the actual costs and derived benefits of extending concurrent shared-track operations. 2. The business case template and risk analysis technique illustrated in Chapter 4 should be adapted to a specific candidate line segment under consideration by a transit agency. The research for this report used hypothetical data for illustrative purposes. Expanding upon this research by applying the method to a real system could validate and calibrate the model, and quantify the benefits in a way that may be transferable to other prospective systems. 3. APTA currently sponsors a shared-track working group that serves to disseminate relevant experiences and information. A more active intervention and role by APTA in promoting this application of technology should be encouraged. One means of doing that is developing new FRA standards for shared-track under the auspices of APTA. The existence of any type of standard may assure that each project will not be treated as the first of its kind by the FRA. An approach similar to PRESS and RTOS programs could be adapted for Shared-Track. Cre- ating standards and self-regulation may obviate some FRA concerns. 4. More structural research is needed, such as computer modeling and simulation of light pas- senger rail cars and freight vehicle collisions. Ideally a real-world test should be performed and results can be incorporated in new CEM designs and risk analysis models. 5. Investigate whether it is possible to use federal funding available for shortline/branchlines reconstruction or rehabilitation for a shared-track service, thus reducing costs to the transit agency. 84 Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner’s Guide

Next: Bibliography »
Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner's Guide Get This Book
×
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

TRB’s Transit Cooperative Research Program (TCRP) Report 130: Shared Use of Railroad Infrastructure with Noncompliant Public Transit Rail Vehicles: A Practitioner’s Guide examines a business case for the shared use of non-Federal Railroad Administration-compliant public transit rail vehicles (e.g., light rail vehicles) with freight operations and highlights a business model for such shared-use operations. The report also explores potential advantages and disadvantages of shared-use operations and the issues and barriers that can arise in the course of implementation.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!