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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>
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    <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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      <title>Ballast Return Rate Assessment for High-Output Ballast Cleaner Thanks to Image-Based Technology and Ballast Degradation Models</title>
      <link>https://trid.trb.org/View/2335366</link>
      <description><![CDATA[Ballast is a high value railway track asset. Its expected lifespan is often expressed in years or cumulative tonnage. However, the high variability of its lifespan can often be related to its interaction with the other components of the superstructure (rail, sleeper etc.) on the one hand but also to the quality/stiffness of the subballast layers, which makes the remaining life expectancy assessment a very challenging task. Ballast fouling is often taken as a key indicator (along with age and geometry data) to schedule a ballast renewal. Modern renewal techniques (High Output Ballast Cleaner) allow in situ ballast re-use with built-in screening of fine elements. New ballast is used to top-up the layer and meet the thickness specification as per track renewal design. With an average total tonnage of 4t per linear meter of track, screening and re-using a fraction of existing ballast can impact significantly the economy and yield of the renewal works. In order to optimize the life cycle of existing ballast and the costs of renewal works (environmental, economic etc.), ballast return rate prediction is paramount. This paper presents an innovative ballast return rate method thanks to a non-destructive image based field methodology (pandoscope®). The images are processed to obtain the grain size distribution of existing ballast and are used to predict the ballast return rates. Case studies on high speed lines as well as conventional lines will illustrate this approach.]]></description>
      <pubDate>Tue, 20 Feb 2024 15:54:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2335366</guid>
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    <item>
      <title>Use of satellite imagery to categorize vegetation on the French railway network (SNCF Réseau)</title>
      <link>https://trid.trb.org/View/2314828</link>
      <description><![CDATA[In order to ensure the safety and regularity of train traffic, as well as the good condition of the railway infrastructures, SNCF Réseau must control the vegetation with efficiency on the network. For this purpose, the French railway infrastructure manager needs to know which kind of vegetation grows on the network. To make the inventory of the vegetation, a processing chain of very high spatial resolution satellite imagery has been developed. The use of a machine learning algorithm for supervised classification and the automation of the processing chain as well as the reuse of pre-trained models allowed to industrialize at a high temporal frequency the inventory of the vegetation along the French railway network.]]></description>
      <pubDate>Wed, 14 Feb 2024 14:33:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2314828</guid>
    </item>
    <item>
      <title>A lightweight numerical model of railway track to predict mechanical stress state in the rail</title>
      <link>https://trid.trb.org/View/1898690</link>
      <description><![CDATA[A new approach is conducted within SMCF Réseau to redefine and improve the current procedure behind rolling stocks admission. A perspective to update computation rules for traffic conditions is to consider track fatigue issues. In this sense, the study aims to provide a better knowledge of stress state induced by moving vehicles in rails through a lightweight numerical model of the track. Specifically, the track model consists of a two-layer discrete support model in which the rail is considered as a beam and sleepers are punctual masses. The rail-pads and ballast layer are modelled as spring/damper couples. Considering the track's vertical response, the study intends to quantify the impact of the vehicle's dynamic overload on the track response and verify the possibility of these overloads to excite track vibration modes. A first study considering constant moving loads already shows negligible effect of track inertia forces due to high track stiffness and damping. This justifies the prediction of mechanical stress state in the rail for fatigue issues through a static model of the track and a simplified dynamic model for the vehicle.]]></description>
      <pubDate>Thu, 20 Jan 2022 12:14:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/1898690</guid>
    </item>
    <item>
      <title>Methodology for Railway Automation Study and Automatic Generation of PLC Programs</title>
      <link>https://trid.trb.org/View/1530108</link>
      <description><![CDATA[This paper presents an original approach to standardization of Electrical Traction's work of railway. This approach was developed within an industrial thesis, financed by the SNCF (French acronym for National Society of French Railways) in association with the CReSTIC (Research Center in Information and Communication Science and Technologies), laboratory of university of Reims Champagne-Ardenne. It consists of two axes of improvement. The first one concerns the standardization and automatic generation of deliverables (wiring diagrams, PLC programs...) established initially by the systems engineers. Therefore these latter will avoid repetitive tasks which can lead to mental underload and then, focus their attention on cognitive tasks. The second axe of the proposed methodology consists in integrating a robust filter based on the use of safety constraints in a PLC program, so that the safety of the system can be ensured whatever the functional program. Thus, this solution guarantees safety without changing the know-how of the systems engineers. This paper presents only the first axe of the proposed methodology.]]></description>
      <pubDate>Mon, 27 Aug 2018 09:48:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/1530108</guid>
    </item>
    <item>
      <title>A risk assessment study on accidents at French level crossings using Bayesian belief networks</title>
      <link>https://trid.trb.org/View/1509070</link>
      <description><![CDATA[Level crossing (LX) safety continues to be one of the most critical issues for railways despite an ever increasing focus on improving design and practices. In the present paper, a framework of probabilistic risk assessment and improvement decision based on Bayesian belief networks (PRAID-BBN) is proposed. The developed framework aims to analyse various impacting factors which may cause LX accidents, and quantify the contribution of these factors so as to identify the crucial factors which contribute most to the LX accidents. A detailed statistical analysis is first carried out based on the accident/incident data. A BBN risk model is established according to the statistical results. Then, the authors apply the PRAID-BBN framework on the basis of the accident/incident data provided by SNCF, the French national railway operator. The main outputs of the authors' study are conducive to efficiently focusing on the effort/budget to make LXs safer.]]></description>
      <pubDate>Thu, 17 May 2018 14:45:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1509070</guid>
    </item>
    <item>
      <title>From Silicon Valley to Gare du Lyon: SNCF embraces design thinking</title>
      <link>https://trid.trb.org/View/1488007</link>
      <description><![CDATA[Design thinking is a concept made famous by Steve Jobs and the Apple company in Silicon Valley and is being embraced by France's national state-owned railway company (SNCF)'s Gares & Connexions as a way to enhance passenger experience at its stations throughout France. This article discusses what has thus far been achieved through this solution-oriented process that emphasizes as central in all development stages a consideration for the consumer in an attempt to achieve innovation.]]></description>
      <pubDate>Mon, 20 Nov 2017 17:09:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1488007</guid>
    </item>
    <item>
      <title>ONCF and SNCF aim to bridge the skills gap</title>
      <link>https://trid.trb.org/View/1481969</link>
      <description><![CDATA[A 50-50 joint venture between Moroccan National Railways (ONCF) and French National Railways (SNCF), Institut de Formation Ferroviaire (IFF) was founded as part of the inter-governmental agreement for a high-speed rail project between France and Morocco in 2007. IFF has the responsibility for equipping supervisors from both ONCF and SNCF with the necessary skills to operate the modern railway. The training process is detailed here.]]></description>
      <pubDate>Wed, 27 Sep 2017 10:17:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/1481969</guid>
    </item>
    <item>
      <title>Will France say "oui" to inOui?</title>
      <link>https://trid.trb.org/View/1482154</link>
      <description><![CDATA[French National Railways (SNCF) is hoping to attract 15 million additional passengers to its high speed network by 2020, under a new strategy made public in May 2017. How the railway plans to reach this ambitious target is explained in this article. SNCF has rebranded its flagship service, the TGV high-speed network, to inOui in an effort to develop and improve TGV by improving its service and image to attract new passengers and bring back others. Changes include arming onboard staff with electronic tablets loaded with passenger profiles, providing a more attentive and personalized service; adding rotating seats in first class to face the direction of travel; utilizing natural and sustainable materials for train interiors; and offering high-speed Wi-Fi onboard. The number of rolling stock in the fleet will be cut in order to reduce passenger operating costs by 30%.]]></description>
      <pubDate>Wed, 27 Sep 2017 10:17:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/1482154</guid>
    </item>
    <item>
      <title>Stations skills go global</title>
      <link>https://trid.trb.org/View/1467519</link>
      <description><![CDATA[France's official railway operator, SNCF, has developed a multi-disciplinary approach to its train stations, as the role of rail hubs in the life of cities from Paris to Tehran is enhanced. This article explains the process of preparing for possible market liberalization for SNCF's stations business, Gares & Connexions, who have formerly experienced competition from only a handful of cross-border trains from Italy. There will be a greater focus on station catering and retail, with remodelling as one of the showpiece projects moving forward.]]></description>
      <pubDate>Thu, 25 May 2017 13:56:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/1467519</guid>
    </item>
    <item>
      <title>Coach deregulation poses another threat to rail</title>
      <link>https://trid.trb.org/View/1376260</link>
      <description><![CDATA[Traffic from France's SNCF main line passenger business is threatened as legislation lifts restrictions on long-distance coach services. As ride-sharing grows at a rate of more than 60% a year, competition for long-distance passenger transport in France is increasing. However, the "Loi Maron," a law intended to promote economic growth, took effect in August 2015 and will intensify this competition. A market analysis and the impacts on rail are explored in this article.]]></description>
      <pubDate>Wed, 23 Dec 2015 08:13:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/1376260</guid>
    </item>
    <item>
      <title>Reactive power compensation in railways based on AC boost choppers</title>
      <link>https://trid.trb.org/View/1328627</link>
      <description><![CDATA[In this study, a new topology, using AC choppers is proposed for reactive power compensation in 25 kV/50 Hz railway networks. The low losses of these converters compared to other solutions such as voltage-sourced inverters-based STATCOMs, makes this approach attractive for high-power, single-phase systems such as railway networks. A possible solution based on the controlled impedance concept working in boost mode is proposed and applied to a substation in the French rail network. Design method presented end simulation results which confirm the performance of this low-cost and low-loss solution. Finally, the experimental results achieved on a 1.2 MVAR prototype are presented.]]></description>
      <pubDate>Mon, 24 Nov 2014 15:13:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/1328627</guid>
    </item>
    <item>
      <title>High-Speed Train Network Routing with Column Generation</title>
      <link>https://trid.trb.org/View/1289871</link>
      <description><![CDATA[This paper is based on an award-winning rail scheduling project. It examines a high-speed train routing problem in which the trains are operated on a large network with sparse stations. The relatively long distance between train stations makes it unlikely to get a backup train unit in time when an operating train is out of service because of the need for maintenance. Therefore, regular maintenance is carefully incorporated into the base routing plan and is strictly enforced. An integrated path-based routing model is proposed here to design train routes and scheduling optimally. The objective is to cover the published trains and timetable with the least cost without violating operational rules and maintenance requirements. The scheduling for each operational cycle needs to be completed in a timely manner and be implementable in practice. A heuristic is proposed to solve the problem in a column generation framework. Numerical tests are conducted with operational data from the French National Railways. The test not only shows a significant cost savings but also indicates its efficiency in real-world applications.]]></description>
      <pubDate>Wed, 26 Mar 2014 10:07:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/1289871</guid>
    </item>
    <item>
      <title>Short line projects start to take off</title>
      <link>https://trid.trb.org/View/1256854</link>
      <description><![CDATA[A handful of operators has succeeded in launching rail freight services in France. The basic idea of an Opérateur Ferroviaire Portuaire (OFP) (port rail operator) is to encourage the establishment of local operators to handle rail freight on lightly-used routes where SNCF (France's national state-owned railway company) could not make its service pay. They would be small and flexible in business structure with staff able to carry out multiple tasks, rending their rail services competitive with road. Several OFPs have entered the scene with more expected in the future, with expected challenges and issues they will face presented here.]]></description>
      <pubDate>Thu, 25 Jul 2013 16:43:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/1256854</guid>
    </item>
    <item>
      <title>National flagship must raise its standard</title>
      <link>https://trid.trb.org/View/1256853</link>
      <description><![CDATA[A reform package unveiled by the French government on May 29, 2013 featured the key pillars of restructuring of infrastructure management, a return to financial equilibrium, and the creation of a strategic authority to oversee a publicly-owned rail sector. Regional authorities are playing a greater role in specifying and funding local rail services. Residual intercity trains on former main lines face an uncertain future. France's national state-owned railway company (SNCF) and Reseau Ferre de France (RFF), which is the French Rail Network that owns and maintains SNCF have established a solid collaboration.]]></description>
      <pubDate>Thu, 25 Jul 2013 16:43:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/1256853</guid>
    </item>
    <item>
      <title>Rail access charges in France: Beyond the opposition between competition and financing</title>
      <link>https://trid.trb.org/View/1226427</link>
      <description><![CDATA[Access charges to the railway infrastructures, and in particular of the high speed lines, poses many theoretical and practical questions. Besides the need to decide whether it is better to apply a principle of marginal cost or a full cost approach, a difficulty arises with regard to the possibilities of competition between various operators. France is especially affected by this problem since access charges are particularly high while at the same time competition is non-existent. Is this absence of competition explained by the high level of access charges? After describing the principles which underlie the pricing scheme for high speed trains in France, this paper attempts to find out if these tolls constitute a barrier to entry. After building a model that summarizes the components of supply and demand on the Paris-Lyon journey, this paper shows that the considerations relating to demand (peak hour or off-peak hour) are more fundamental than access charges, which do not in themselves constitute a barrier to entry. Barriers exist, but they involve access charges in relation to the allocation of slots which would make it possible to guarantee certain profitability to a new entrant. Break-even points are proposed which show that French National Railway Corporation (NCF)'s potential competitors have margins for manoeuvre.]]></description>
      <pubDate>Thu, 17 Jan 2013 13:49:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/1226427</guid>
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