Train-Track Interaction

The Train-Track Interaction sector represents an intersection of the rolling stock, track and structure sectors. Its main purpose is to study the interaction and interfaces between vehicles and infrastructure by means of a systemic, holistic approach. The TTI Sector is currently chaired by Pierre-Etienne Gautier, Director of BIM and Digital Twin/Continuity at SNCF Réseau (France).

The TTI Sector, Rolling Stock Sector, Track Expert Group (TEG) and Panel of Structural Experts (PoSE) coordinate their activities and seek out synergies on an ongoing basis. Potential synergies with the UIC Energy, Environment and Sustainability (EES) platform and, more generally, with the Passenger and Freight forums, have been identified thus far.

TTI activities

The TTI Sector’s activities are aimed at optimising the operational, economic and environmental efficiency of the railway system, ensuring its safety and improving interoperability.

The following key technical areas have been identified in this regard, constituting the scope of the TTI Sector’s activities:

  • Safety in relation to track/vehicle dynamics and derailment prevention
  • Vehicle homologation
  • Clearance (track loading) gauge compatibility
  • Noise and vibration
  • Aerodynamics
  • Pantograph/catenary mechanical interaction (not including energy management)
  • Remote measurement
  • Cost efficiency
  • Technological innovation and disruptive ground transportation methods

A permanent core expert group provides skills in cross-functional areas such as safety, technological innovation and cost efficiency. The core expert group steers activities and defines the topics for which further research is to be conducted.

Main objectives

The first working groups (WGs) to be launched in the TTI Sector were focused on aerodynamics and acoustics and on pantograph/catenary mechanical interaction. This decision was taken by the Sector’s advisory board based on the needs identified. Since then, the ad hoc working groups have developed networks of recognised experts from these different technical areas.

The acoustics and aerodynamics working groups were formed in 2017, followed later by a WG for interaction. At the groups’ kick-off meetings, it was agreed that the groups would draft and publish three different white papers on each of their specialist areas by the end the year to provide a basis for future projects, IRSs and activities focusing on these areas.

The first, a White Paper focused on aerodynamics, was published in 2018 and is available for download free of charge in the ETF Shop.

The second, a White Paper on acoustics, was completed in 2019 and published in March 2020.

Among other activities, the TTI Sector is currently involved in the “Effects of Instabilities on Track Resistance and Fatigue” project, which seeks to verify the acceptable limits of vehicle instability in relation to superstructure resistance and fatigue damage.

The TTI Sector has also concluded its activities in respect of prevention and mitigation of derailments (PMD). This project was developed with the aim of defining recommendations for harmonisation of the assessment procedure for running vehicles and limit values throughout Europe.

Current PMD expertise is documented in IRS (International Railway Solution) 70729, which was published in October 2019. This IRS is based mainly on findings from the ALC, HRMS and D-RAIL projects, and is an example of the important role fulfilled by UIC in implementing valuable results from previous projects.

In 2020, a new project on a common codification methodology for railway gauges (“G-CODE”) is being proposed as part of the opt-in process with a view to project launch in 2021 in cooperation with the Freight Forum. The aim of this project will be to identify a harmonised methodology to strengthen communication and cooperation between IMs and RUs, increase transparency in relation to access conditions for railway lines, promote the use of lines by RUs and facilitate planning and optimisation of routes, all with the general aim of attracting additional traffic for rail and improving interoperability on the international network, including in the EU.

Additionally, the HARMOTRACK (“Harmonisation of Track Quality Description and Assessment”) project, which was restarted in 2018 after a two-year break, will result in a dedicated new IRS: “Recommendations for use of track geometry and dynamic measurement systems. Description of specific applications”.

A new project was launched in 2019: ”Sidewind Assessment for Infrastructure and Rolling Stock (SAFIRST)”, with the general aim of obtaining reference characteristic wind curves distinct from those already established for high-speed trains (> 250 km/h), defining common European methods for assessing wind exposure on railway lines, proving safety with regard to crosswind effects, and addressing each of these topics within the context of climate change.

Two further projects have already started in 2020, both related to aerodynamics. The first is the “Crossing Effects between Trains (CROSS-T)” initiative, which will cover the assessment of gaps for aerodynamics-related phenomena, and the related mitigation measures and operational rules in mixed traffic lines, between high-speed trainsets and freight train compositions, which is still a requirement in the context of TSIs and EN standards.

The second project deals with “Aerodynamic Noise (AERO NOISE)”, which aims to respond to the need for better control of aerodynamic noise sources in a high-speed trainset during operations. Such noise may originate from a variety of areas in the train, including: pantograph, pantograph recess, inter-coach gaps, front of train, connection cables, low-level turbulence, etc. These sources of noise have a significant influence on the effectiveness of mitigation measures such as noise barriers.

In addition to IRS 70729, which has been published, and IRS 60661, which is due to be published in 2020, a further 17 IRSs and technical reports are currently being drafted.

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