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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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    <item>
      <title>High-Order Internal Model-Based Data-Driven Iterative Learning Control of High-Speed Railways Subject to Faded Channels</title>
      <link>https://trid.trb.org/View/2672814</link>
      <description><![CDATA[This study investigates the high-order internal model (HOIM) based data-driven iterative learning control of HSRs subject to faded channels. Firstly, the nonlinear train dynamics are converted into an input/output data-based model by using a linearization approach. Then, the HOIM of the desired speed trajectories is introduced and the fading channel is used to model the unreliable transmission network. Next, the model free adaptive iterative learning control (MFAILC) strategy is implemented based on the train input and faded output information, and the theoretical convergence analysis of the speed error is carried out. Eventually, the validity of the MFAILC scheme is checked in simulation by applying the CRH-380 HSRs on a StarSim hardware-in-loop semi-physical platform.]]></description>
      <pubDate>Wed, 24 Jun 2026 11:31:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/2672814</guid>
    </item>
    <item>
      <title>Lagrangian relaxation based speed trajectory optimization for multiple trains under virtual coupling with operational state transition</title>
      <link>https://trid.trb.org/View/2618293</link>
      <description><![CDATA[The utilization of virtual coupling in train operations offers significant potential to increase the railway transport capacity. Different from traditional signaling systems, virtual coupling allows trains to be coupled and decoupled during operation. As a result, train operations under virtual coupling differ fundamentally from those under conventional signaling systems. Therefore, traditional speed trajectory optimization methods used for regular operations are insufficient for the operation of virtually coupled trains. To optimize the speed trajectories under virtual coupling, a mixed integer nonlinear programming model is formulated. This model explicitly represents the different operational states of virtual coupling using binary variables, and there are time window constraints restricting the times of state transitions. The original model is converted into a linear model by a piecewise-linear approach. With the aim of enhancing computational efficiency, a Lagrangian relaxation method is adopted, where the dual problem can be solved efficiently because the safety distance constraints are relaxed. To provide evidence of the proposed method’s effectiveness in coupling and decoupling scenarios, numerical experiments are conducted based on a part of the Beijing-Shanghai high-speed railway. The results show that our model effectively optimizes the speed trajectories for virtually coupled trains while satisfying safety distance and time window constraints. In the coupling scenario with two trains, compared with using CPLEX directly, the speed trajectories obtained by LR have smaller energy consumption and larger train distance. The total objective function obtained by LR is 1.05 % lower. Moreover, in some cases with the coupling process where the direct method cannot find any feasible solution, LR can solve the problem within the same computational time limit, demonstrating that LR significantly improves computational efficiency in coupling scenarios.]]></description>
      <pubDate>Wed, 17 Jun 2026 16:14:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/2618293</guid>
    </item>
    <item>
      <title>A Process-Oriented and Coalescent Analysis Method for Safety and Security in Railway Systems</title>
      <link>https://trid.trb.org/View/2625410</link>
      <description><![CDATA[The convergence of network, electronic, and control technologies has expanded the attack surface of industrial control systems (ICSs), necessitating the integration of functional safety and cybersecurity. Existing methods often treat safety and security as isolated domains, overlooking their interdependence in modern ICSs. This article proposes a novel methodology, Process-Oriented and Coalescent Analysis (POCA), to bridge this gap through an integrated safety and security analysis. Unlike previous approaches, POCA focuses on the intersection of cyberthreats and functional interactions, offering a new perspective on threat modeling. Applied to a railway signal system, a representative ICS that has received insufficient attention in cybersecurity research, POCA incorporates cyberattack scenarios, system service processes, and safety constraints to identify and assess risks. The analysis results highlight POCA’s effectiveness in uncovering vulnerabilities at the intersection of functional safety and cybersecurity, providing actionable insights for system design and operation.]]></description>
      <pubDate>Mon, 23 Feb 2026 11:23:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2625410</guid>
    </item>
    <item>
      <title>Convolutional neural networks for accurate measurement of train speed</title>
      <link>https://trid.trb.org/View/2610793</link>
      <description><![CDATA[In this study, we explore the use of Convolutional Neural Networks for improving train speed estimation accuracy, addressing the complex challenges of modern railway systems. We investigate three CNN architectures — single-branch 2D, single-branch 1D, and multiple-branch models — and compare them with the Adaptive Kalman Filter. We analyse their performance using simulated train operation datasets with and without Wheel Slide Protection activation. Our results reveal that CNN-based approaches, especially the multiple-branch model, demonstrate superior accuracy and robustness compared to traditional methods, particularly under challenging operational conditions. These findings highlight the potential of deep learning techniques to enhance railway safety and operational efficiency by more effectively capturing intricate patterns in complex transportation datasets.]]></description>
      <pubDate>Fri, 09 Jan 2026 16:59:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/2610793</guid>
    </item>
    <item>
      <title>Quick-Response Research on Long-Term Strategic Issues. Task 55. Impact of Positive Train Control</title>
      <link>https://trid.trb.org/View/2636147</link>
      <description><![CDATA[Positive train control (PTC) is an advanced rail safety technology designed to mitigate human error and improve operational safety. It reduces the risk of accidents by preventing or reducing train-to-train collisions, overspeed derailments, improperly lined switches, and unauthorized incursion into work zones. Public transportation agencies that operate commuter and intercity passenger rail services have been required to have PTC installed since 2020. To meet this deadline, agencies had to invest immense resources into new infrastructure and specially trained staff to develop and test the system. 

While PTC implementation has been extensively documented, less is known about its long-term operational impacts, realized safety benefits, and opportunities for leveraging PTC investments beyond regulatory compliance. Now that agencies have been operating with PTC for several years, research is needed to examine and document how PTC has affected passenger rail safety and how PTC-related infrastructure, data, and workforce capabilities can be leveraged to further enhance safety, security, and operational performance.

OBJECTIVE: The objective of this research is to document and quantify the safety, operational, and organizational impacts of PTC on passenger rail operations subject to the Rail Safety Improvement Act of 2008, and to identify lessons learned, current practices, and benefits realized beyond statutory and regulatory minimum requirements.

RESEARCH PLAN: The TCRP is seeking proposals on how best to achieve the research objective. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and subaward time. Proposals must present the proposers' current thinking in sufficient detail to demonstrate their understanding of the issues and the soundness of their approach to meeting the research objective.

The research, at a minimum, shall: (1) Identify and summarize existing literature, industry practices, and other relevant resources on the operational safety of PTC. (2) Document the current state of PTC implementation, use, and maintenance across passenger rail agencies. (3) Assess the realized benefits of PTC implementation on passenger rail safety, including operations involving shared-use corridors, passenger operators hosting freight tenants, and passenger operators operating on freight-owned infrastructure.
(4) Quantify, to the extent practical, the safety benefits attributable to PTC systems using available industry data and performance measures. (5) Identify innovative applications of PTC-related infrastructure, data, technologies, and workforce capabilities that extend beyond statutory and regulatory minimum requirements and improve safety, security, and operational efficiency. (6) Examine PTC operating, maintenance, and lifecycle costs to determine eligibility for capitalization or federal funding assistance and identify any relevant statutory, regulatory, or policy considerations.
Proposers are encouraged to identify innovative approaches for collecting information (e.g., stakeholder interviews, focus groups, workshops, surveys, peer exchanges) and for presenting research findings (e.g., case studies, implementation guidance, checklists, fact sheets, other practitioner-oriented tools).

The research plan shall be divided into tasks that detail the work proposed. The research plan shall describe appropriate deliverables (which also represent key project milestones), including, at a minimum: (1) An amplified research plan that responds to comments provided by the project panel at the subawardee selection meeting. (2) An interim report and panel meeting. The interim report should include the analyses and results of completed tasks, an update of the remaining tasks, and a detailed outline of the final research product(s). The panel meeting will occur after the panel review of the interim report. The interim report and panel meeting should occur after the expenditure of no more than 40 percent of the project budget. (3) Final deliverables. The final deliverables should include a conduct of research report documenting the entire research effort. (4) A technical memorandum titled “Implementation of Research Findings and Products” (see Important item IV). (5) A slide deck to be used in webinars that presents the research findings and conclusions.
The research team may include additional deliverables and additional panel meetings via teleconference in the research plan. The research plan shall have a schedule for the project that includes 1 month for panel review of the interim report and 3 months for panel review of the draft final report and for the research team's revision of the draft final report.

IMPORTANT: (1) The brochure Information and Instructions for Preparing Proposals for the Transportation Research Board’s Cooperative Research Programs includes extensive guidance on the preparation of acceptable proposals for submission to CRP. Revisions to these instructions are highlighted in yellow within that document. (2) Proposals will be rejected if any of the proposed research team members work for organizations represented on the project panel. The panel roster for this project can be found here. Proposers may not contact panel members directly; this roster is provided solely for the purpose of avoiding potential conflicts of interest. (3) The text of the final deliverable is expected to be publication ready when it is submitted. It is strongly recommended that the research team include the expertise of a technical editor as early in the project timeline as possible. See Appendix F of the Procedural Manual for Subawardees Conducting Research in the Transportation Research Board’s Cooperative Research Program for technical editing standards expected in final deliverables. (4) The required technical memorandum titled “Implementation of Research Findings and Products” should (a) provide recommendations on how to best put the research findings/products into practice; (b) identify possible institutions that might take leadership in applying the research findings/products; (c) identify issues affecting potential implementation of the findings/products and recommend possible actions to address these issues; and (d) recommend methods of identifying and measuring the impacts associated with implementation of the findings/products. Implementation of these recommendations is not part of the research project and, if warranted, details of these actions will be developed and implemented in future efforts. (5) The National Academies have an ethical and legal obligation to provide proper attribution whenever material from other sources is included in its reports, online postings, and other publications and products. TRB will review all Cooperative Research Programs draft final deliverables using the software iThenticate for potential plagiarism. If plagiarized text appears in the draft final deliverable, the research team will be required to make revisions and the opportunity to submit future proposals may be affected. 

Proposals must be uploaded via this link: https://www.dropbox.com/request/v0aoa3vrj1pnawlnz17t 
Proposals are due not later than 5:00 p.m. Eastern Time on 8/18/2026.
This is a firm deadline, and extensions are not granted. In order to be considered for award, the agency's proposal must be in our offices not later than the deadline shown, or the proposal will be rejected.

General Notes: (1) Regarding non-discrimination practices and policies, proposers are required to comply with applicable federal and state laws and regulations (including without limitation, federal civil rights laws, regulations, and requirements) and follow applicable federal guidance, except as the Federal Government determines otherwise in writing. Without limitation of the foregoing, proposers agree to prohibit discrimination as prescribed by Title VII of the Civil Rights Act of 1964. (2) The essential features required in a proposal for research are detailed in the current brochure entitled "Information and Instructions for Preparing Proposals". Proposals must be prepared according to this document, and attention is directed specifically to Section IV for mandatory requirements. Proposals that do not conform with these requirements will be rejected. (3) The total funds available are made known in the project statement, and line items of the budget are examined to determine the reasonableness of the allocation of funds to the various tasks. If the proposed total cost exceeds the funds available, the proposal is rejected. (4) All proposals become the property of the Transportation Research Board. Final disposition will be made according to the policies thereof, including the right to reject all proposals.
(5) Potential proposers should understand that follow-on activities for this project may be carried out through either a contract amendment modifying the scope of work with additional time and funds, or through a new contract (via sole source, full, or restrictive competition).]]></description>
      <pubDate>Mon, 08 Dec 2025 20:06:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/2636147</guid>
    </item>
    <item>
      <title>Quantitative Dependability Evaluation of Train Control Systems in Presence of Uncertainty: A Systematic Literature Review</title>
      <link>https://trid.trb.org/View/2553293</link>
      <description><![CDATA[Technological advances in modern Train Control Systems (TCSs) promise to improve dependability of railway transportation in terms of safety, availability, and capacity, notably by employing novel distancing policies such as Moving Block (MB) signaling and Virtual Coupling (VC), fueled by advanced train localization methods such as satellite positioning. At the same time, these technological advances raise notable concerns about the effects that uncertainty in critical TCS parameters (such as train position and speed) may have on dependability-related attributes. Recently, various approaches have been proposed to characterize such effects through quantitative measures, leveraging formal stochastic modeling and evaluation of the TCS behavior. In this paper, we illustrate the results of a systematic review of the literature on quantitative evaluation of dependability-related attributes of TCSs under uncertainty on vital parameters. Specifically, we have finally selected 42 relevant papers, published between 2011 and 2023, that succeed in giving, through an empirical perspective and classification, a comprehensive view of current research and practice in quantitative dependability assessment of TCSs.]]></description>
      <pubDate>Thu, 06 Nov 2025 16:53:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2553293</guid>
    </item>
    <item>
      <title>Positive Train Control Survey</title>
      <link>https://trid.trb.org/View/2582908</link>
      <description><![CDATA[In the fall of 2011 William Craven and Frank Sharpless submitted a research request for a survey of commuter rail systems to determine how these systems were responding to the Federal Railroad Administration mandate for installation of Positive Train Control (PTC) by December 31, 2015. The research request was approved by the C-RAC and FHWA in June 2012 and included in the Research Bureau’s FY2013 Work Plan. Amy Estelle was the Project Manager for Research. She took a list of systems provided by the Rail Bureau and made email and telephone inquiries to determine who at each system could best answer questions regarding PTC. She developed a survey with input from the Rail Bureau. The Research Bureau purchased a subscription to SurveyMonkey software to conduct the survey online. On October 15, 2012 the survey was sent out to contacts at 15 commuter rail systems. On October 17, 2012 the survey was sent out to an additional recipient. Six out of 16 systems responded for a 37.5% response rate. Attached are the email list, a record of contacts made with commuter rail systems, a summary and individual survey results.]]></description>
      <pubDate>Tue, 21 Oct 2025 11:36:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2582908</guid>
    </item>
    <item>
      <title>Design of the Maximum Operating Speed of Passenger and Freight Trains with Advanced Train Control System in Mixed Operations</title>
      <link>https://trid.trb.org/View/2263970</link>
      <description><![CDATA[After the advanced train control systems (e.g., ATP, ATC) have been introduced in Chinese railway, how to determine the maximum operating speeds matched between passenger and freight trains and relative coefficients, theoretically and practically instead of by rough estimate, becomes very important for the mixed operations in China. This paper expounds the quantitative relation among the major coefficients of speed deceleration process, such as the maximum operating speed, the stage numbers divided, and the corresponding speed. And based on it, this paper models the calculation of the optimal matching speed of passenger and freight trains with various stage-control methods in mixed operations, presents a algorithm for the solution and justifies it with a practical example.]]></description>
      <pubDate>Thu, 02 Jan 2025 10:14:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/2263970</guid>
    </item>
    <item>
      <title>Improvement of Key Management Mechanism for RSSP-II and Its Formal Modeling and Verification</title>
      <link>https://trid.trb.org/View/1975916</link>
      <description><![CDATA[As the Railway Signal Security Protocol (RSSP)-II protocol has hidden dangers in the management of transport keys and authentication keys, in order to strengthen the safety of the key management of RSSP-II and make the communication between the safety-related entities of the train control system safer and more reliable, an improved scheme is presented in this paper. This scheme adopted the Raft algorithm combined with elliptic curve cryptography and time-triggered mechanism to get all safety-related devices in a certain area of the system to update and consistently share an authentication key in a way that works without key management center and reduces human intervention. Then, the specification language TLA+ is used to model the consensus process, and the TLC model checker is used to verify the properties of the model. The results show that the scheme is feasible, safe and can simultaneously avoid the deadlock problem. At last, the safety analysis shows that the scheme is safe and meets EN50159 standard.]]></description>
      <pubDate>Wed, 23 Oct 2024 09:00:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1975916</guid>
    </item>
    <item>
      <title>Positive Train Control Communication Failures and Their Impacts: Case Study Using Generalized Train Movement Simulator</title>
      <link>https://trid.trb.org/View/2431661</link>
      <description><![CDATA[Railroads with Positive Train Control (PTC) are experiencing increased delays due to communication failures and outages, during which trains are compelled to move at slower speeds while operating in non-PTC fallback mode. The Federal Railroad Administration (FRA) sponsored Decisiontek, LLC to further enhance the Generalized Train Movement Simulator (GTMS) in 2020. To evaluate the operational impacts of communication outages, the team extended the GTMS to include a Communications Failure Impacts Model.]]></description>
      <pubDate>Mon, 23 Sep 2024 11:18:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2431661</guid>
    </item>
    <item>
      <title>An Investigation of the Effects of Positive Train Control Systems on Track Maintenance</title>
      <link>https://trid.trb.org/View/2425124</link>
      <description><![CDATA[The Federal Railroad Administration (FRA) contracted Transportation Technology Center, Inc. (TTCI) to conduct a broad analysis of the impacts of Positive Train Control (PTC) systems and technology on track maintenance. This research was conducted between September 2019 and September 2020. This report documents the activities of the effort, including a review of the project objectives, an overview of PTC systems and technology in the context of track maintenance and roadway worker protection (RWP), and an analysis of the potential areas that PTC might affect track maintenance. In coordination with FRA, TTCI generated a list of possible effects of PTC on track maintenance to guide the research.]]></description>
      <pubDate>Sat, 07 Sep 2024 16:34:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2425124</guid>
    </item>
    <item>
      <title>Railway Signal Digitalization with the European Rail Traffic Management System and Positive Train Control: Industry 4.0 Expectations and Reality</title>
      <link>https://trid.trb.org/View/2414224</link>
      <description><![CDATA[Positive train control (PTC) and European Rail Traffic Management System (ERTMS) are digital railway signal systems in North America and Europe, respectively. They are frequently described as interchangeable, but they are not. This paper explains the history and motivations for each continent, and the general technical and capability differences between the two signal systems. In general, North America revised their signal systems to respond to safety concerns, and Europe committed to replacing their signals to encourage cross-border train traffic. ERTMS is significantly more expensive than PTC, and the cost has been justified with expectations of greater capacity. Multiple studies find no basis for large capacity increases after implementation of ERTMS. In addition, the added cost of ERTMS threatens an already weak rail freight market in Europe.]]></description>
      <pubDate>Fri, 09 Aug 2024 08:40:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2414224</guid>
    </item>
    <item>
      <title>A holistic solution to virtual coupling based urban rail train control system</title>
      <link>https://trid.trb.org/View/2395119</link>
      <description><![CDATA[Virtual coupling (VC) is an emerging concept that is gaining popularity in railway control systems. It has the potential to significantly enhance railway capacity and flexibility, and has attracted considerable research attention. This study explores several key aspects of VC research in the context of urban rail transit systems, including system structure, train platoon control method, scenario definition, and train scheduling. The paper presents three main contributions: Firstly, it proposes a potential system structure for VC and discusses infrastructure occupancy procedures within typical operational scenarios. Secondly, a VC platoon controller based on the adaptive back-stepping method is designed to realize the function of the operation layer. Thirdly, combining operational scenario definition and control methods, the authors propose a VC train scheduling method based on mixed integer linear programming (MILP). A case study demonstrated that the proposed solution could effectively achieve the primary functions of VC.]]></description>
      <pubDate>Tue, 23 Jul 2024 17:43:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2395119</guid>
    </item>
    <item>
      <title>Parameter optimization of electromagnetic suspension-type maglev train control system based on multi-objective grey wolf non-dominated sorting hybrid algorithm-? hybrid algorithm</title>
      <link>https://trid.trb.org/View/2381944</link>
      <description><![CDATA[This paper presents a novel hybrid algorithm based on CMOGWO-ADNSGA-II to solve the vibration stability problem during the operation of a EMS-type maglev train dynamics model subjected to strong non-linear magnetic buoyancy. The proposed algorithm optimizes the control system parameters of EMS-type maglev train suspensions by combining an improved multi-objective chaotic grey wolf algorithm (CMOGWO) with an improved non-dominated Sorting genetic algorithm-II (ADNSGA-II) to enhance the search capability of the algorithm and ensure population diversity. The efficacy of the algorithm is demonstrated by applying it to the EMS-type maglev train suspension frame control system to find the optimal control parameters. Experimental results show that the system with the optimal parameters applied significantly reduces the suspension gap amplitude and the corresponding standard deviation, as well as the vertical acceleration amplitude and the corresponding standard deviation during operation. The proposed algorithm provides a good solution for EMS-type maglev train suspension vibration control, which can improve its performance and safety.]]></description>
      <pubDate>Thu, 11 Jul 2024 13:54:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/2381944</guid>
    </item>
    <item>
      <title>Study on the System Design and Optimal Models of Urban Rail Transit Traction Calculation System</title>
      <link>https://trid.trb.org/View/2203476</link>
      <description><![CDATA[Urban rail transit traction calculation plays an important role in the urban rail transit design. In this paper, the design objectives of this system are determined, which are to simulate the rail transit traction operation dynamically and real-time optimize the train operation through the dynamic combination of basic control strategies. Furthermore, the architecture and function of this system are analyzed and designed, and the system structure can be divided into four parts, including a basic data management subsystem, a traction automatic calculation subsystem, a human-computer interaction subsystem, and a data out subsystem. Moreover, the key technologies of the system are studied, including a multi-objective train operation model and traction calculation algorithm design. Finally, the system is proved to be effective by simulation train operation in Guangzhou Metro Line 3.]]></description>
      <pubDate>Mon, 17 Jun 2024 14:45:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2203476</guid>
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