João Pombo

University of Huddersfield, School of Computing & Engineering, Faculty Member

Heriot-Watt University, School of Energy, Geoscience, Infrastructure and Society, Faculty Member

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João Pombo is Professor of Railway Technology at the Institute of Railway Research, University of Huddersfield, UK, with a PhD and Post-Doc in Mechanical Engineering by the University of Lisbon, Portugal. He is a specialist in railway engineering and technology with more than 24 years’ experience and has been involved in Research and Development (R&D) activities involving train and track dynamics, vehicle-infrastructure and pantograph-catenary interaction, structural analysis, condition monitoring, wear, maintenance and optimization. He has led and participated in several national and international projects in close collaboration with leading international research centres and key industry players. He also has more than three years’ working experience at BOMBARDIER and ALSTOM. João Pombo’s R&D work has been awarded four innovation prizes and he is author of more than 170 papers in refereed journals and international conferences. He is the editor-in-chief of the “International Journal of Railway Technology”, chairman of the "International Conference on Railway Technology" series and editorial board member of the journals “Multibody System Dynamics” and “Energies - Electric Vehicles”.
Phone: +441484257179
Address: Institute of Railway Research, University of Huddersfield, Queensgate, HD1 3DH Huddersfield

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Papers by João Pombo

Enhancing pantograph-catenary dynamic performance using an inertance-integrated damping system

Vehicle System Dynamics, Feb 11, 2021

For modern electrical rail systems, the pantograph-catenary dynamic performance, usually assessed... more For modern electrical rail systems, the pantograph-catenary dynamic performance, usually assessed by the contact forces, is one of the most critical challenges. Too much fluctuation in these forces can lead to either accelerated wear of the contacting components or losses of contact and, consequently, arcing. In this work, inertanceintegrated pantograph damping systems are investigated with the objective of reducing the contact forces standard deviation. Firstly, a multibody pantograph model is developed with its accuracy compared with published experimental data. The model is improved through the calibration of the pantograph head suspension parameters and the introduction of both a non-ideal joint and flexibility effects. Using the calibrated model, beneficial inertance-integrated damping systems are identified for the pantograph suspension, where the pantograph interacts with the catenary. The results show that the configuration with one inerter provides the best performance among other candidate layouts and, contend a 40% reduction of the maximum standard deviation of the contact force over the whole operating speed range in the numerical modelling scenario analysed. Considering the identified configuration, time-domain analysis and modal analysis are investigated. It has been shown that the achieved improvement is due to the fact that with the beneficial inertance-integrated damping system, the first resonance frequency of the pantograph system coincides with the natural frequency of the catenary system.

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Civil-Comp Special Issue

Computers & Structures, Oct 1, 2009

ABSTRACT This paper shows the application of neural networks in a multiscale analysis of a reinfo... more

A Comparative Study between Two Pantographs in Multiple Pantograph High-Speed Operations

The international journal of railway technology, 2013

Pantograph-Catenary Dynamic Studies on Contact Wire Gradients Considering Aerodynamic Effects

Analysis of Pantograph Aerodynamic Loads using Computational Fluid Dynamic Studies

Research on Wheel-rail Adhesion Characteristics of High-speed Railway on Long Ramp

Rail pad stiffness estimation based in machine learning algorithms

1K1 Multidisciplinary Research Topics in Railway Engineering(Keynote Lecture)

Proceedings of International Symposium on Seed-up and Service Technology for Railway and Maglev Systems, 2015

Research, Development and Maintenance Conference Editor & Chairman

Fast approximation of critical velocities on high speed rail lines

Scoping prediction of railway critical velocity

Prediction of mechanical properties of rail pads under in-service conditions through machine learning algorithms

Advances in Engineering Software, 2021

Highlights • This study focuses on rail pads fabricated in EPDM, TPE and EVA • Pads' stiffness wa... more Highlights • This study focuses on rail pads fabricated in EPDM, TPE and EVA • Pads' stiffness was predicted through Machine Learning from the working conditions • The importance of each in-service condition was ascertained • The dependency of each working condition on the stiffness was estimated. • An application capable of predicting rail pad stiffness was developed

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Railway critical velocity – Analytical prediction and analysis

Transportation Geotechnics, 2016

When high speed trains travel close to the wave propagation velocity of the supporting track-grou... more When high speed trains travel close to the wave propagation velocity of the supporting track-ground system, large amplitude track deflections are generated. This has safety implications, and also results in a significant increase in track maintenance due to subgrade deterioration. Thus, this paper presents a method to rapidly predict the speed at which these ‘critical velocity’ effects occur. The method is based upon a dispersion analysis of both the track (either ballast or non-ballasted/slab track) and the underlying ground, which are treated as uncoupled systems. Unlike previous approaches, the new calculation approach is fully automated thus not requiring any post-processing to extract the soil dispersion curve. It also works for soil layers of arbitrary depth, uses minimal computing power and can calculate critical speeds associated with higher soil modes. The dispersion based method can be deployed on new/existing lines via a drop-weight test, or using existing geotechnical data. Its accuracy is tested by comparing the results against an alternative semi-analytical, quasi-static railtrack model, and found to be 97% accurate. The code is useful for railway track infrastructure design and its short run times mean it can be used as a scoping tool for newly proposed high speed railroad lines. To obtain new insights into the key variables effecting critical velocity, a sensitivity analysis is undertaken using 1000 random soil profiles. It is found that on average, for the same track height, slab tracks are less likely to encounter critical velocity issues than ballasted tracks because their critical speed is typically 11% higher. It is also shown that track height plays an important role with increases in slab track thickness and reductions in ballasted track thickness both causing increases in critical velocity. Furthermore, it is found that soil saturation affects critical speed considerably (by up to 12–17% depending on track type) because changes to Poisson’s ratio alter the dispersion characteristics of layered soils in the mid-frequency range, where critical velocity effects occur. Finally, it is shown that railpad stiffness has a low influence, and that increasing the rail bending stiffness on ballasted tracks increases critical speed.

Parametric analysis of railway infrastructure for improved performance and lower life-cycle costs using machine learning techniques

Advances in Engineering Software

Track and catenary reconstruction from aerial images for the realistic analysis of rail electrification systems

Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit, Jun 28, 2023

Currently, the modelling of the railway catenaries for straight tracks is well understood and dem... more Currently, the modelling of the railway catenaries for straight tracks is well understood and demonstrated via an accepted number of applications and an international benchmark. However, in the presence of a general track geometry, including curved tracks, challenges still remain. The fundamental difficulty is how to address the catenary layout in the presence of curves for a long railway track in which a large number of catenary sections are defined. To support the catenary design, e.g. in new electrification projects, it is fundamental to identify the track geometry, which is not always accessible to the overhead line engineers. This work purposes a novel approach for track geometry reconstruction using aerial views. The reconstruction methodology is based on the general geometry rules for track design. The track geometry obtained is then used as the reference to define the layout of the catenary. The Network Rail Series 1 overhead equipment is used here and the 3D finite element model of the catenary is built on the curved track geometry. The results of this work demonstrate, not only the advances proposed to study more realistically the pantograph-catenary interaction, but also the need to consider general curved tracks in acceptance and interoperability studies.

A co-simulation approach to the wheel–rail contact with flexible railway track

Multibody System Dynamics, Oct 18, 2018

The standard approach to railway vehicle dynamic analysis includes running the vehicle multibody ... more The standard approach to railway vehicle dynamic analysis includes running the vehicle multibody models in rigid railway tracks. The wheel-rail contact, independently of the rolling contact model used, is either handled online or via lookup tables. This traditional approach disregards the coupling effects between the railway vehicle dynamics and the railway track flexibility. In this work the assumption of rigidity of the railway track is released and a finite element model of the complete track, i.e., rails, pads, sleepers, ballast and infrastructure, is used to represent the track geometry and flexibility. A rail-wheel contact model that evaluates the contact conditions and forces is used online. The dynamics of the railway vehicle is described using a multibody methodology while the track structure is described using a finite element approach. Due to the fact that not only the multibody and the finite element dynamic analysis use different integration algorithms but also because the vehicle and track models are simulated in different codes a co-simulation procedure is proposed and demonstrated to address the coupled dynamics of the system. This approach allows to analyse the vehicle dynamics in a flexible track with a general geometry modelled with finite elements, i.e., including curvature, cant, vertical slopes and irregularities, which is another novel contribution. The methodology proposed in this work is demonstrated in an application in which the railway vehicle-track interaction shows the influence of the vehicle dynamics on the track dynamics and vice-versa.

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Railway vehicle speed control in a mountainous track

Pantograph-catenary interaction in curved railway tracks

An approach for the dynamic analysis of pantograph-catenary interaction in curved tracks or in an... more An approach for the dynamic analysis of pantograph-catenary interaction in curved tracks or in any generalized track trajectory is presented here. Both the catenary model and the trajectory path of the pantograph are consistent with the general geometry, which is defined as parametric curve with an associated local reference frame that defines the orientation of the track running surface. The track geometry is obtained using the standard information required for railway vehicle dynamics applications, i.e., curvature, cross level and vertical profile as function of the track arc-length. The finite element method is used to model and evaluate the dynamic behavior of a catenary system. To cope with the general geometry of the track and the path of its base, the pantograph model is developed using a spatial multibody dynamics formulation. The pantograph base motion, which is fixed to the railway vehicle roof, is defined by a prescribed kinematic motion constraint. As both pantograph and catenary use different formulations, their interaction is established through a co-simulation procedure where a penalty method is used to evaluate the contact force between the pantograph and the catenary. To demonstrate the proposed procedure, a detailed analysis of a pantograph-catenary interaction problem is presented here for a catenary model inserted in a track with a geometry including different curve radii