Keywords: continuous monitoring, track maintenance, safety, railways, vibration, multibody.

Safety and comfort are issues of major concern for rail network infrastructure owners and they are significantly affected by track geometrical defects. Track irregularity varies continuously during network operation and, as a consequence, a continuous monitoring is required, but the conventional procedure for rail track diagnostic is time and cost consuming, since it is normally performed by means of diagnostic dedicated vehicles.

In this paper an alternative system for continuous monitoring [1] of track quality in urban rail networks is described, which is being developed in the PM 'n' IDEA project, co-funded by the European Commission within the 7th Framework Program. The paper shows the diagnostic system design by means of time domain multi-body simulations [2,3]. Simulations were used to virtually reproduce the track quality measurement process, allowing for the selection and tuning of the most promising identification method.

In detail, two different approaches were investigated, making always reference to the Metro Roma test case. The first one is meant to define a "track signature", corresponding to an optimal track quality state. Admissible deviations from the signature need to be specified, which correspond to track quality conditions worsened to a point where maintenance is required. In the second "model-based" approach, the rail vehicle is seen as a MIMO dynamic system whose dynamics is excited by the track irregularity. By setting up a properly tuned mathematical model, the vehicle transfer matrix is defined, and the track irregularity input to the system is identified through the output vibration measurement.

The full paper reports meaningful examples concerning both the processing of the acceleration data and the results of the track irregularity identification procedure. The obtained results show a good agreement between the identified track irregularity and the input irregularity exciting the dynamic behaviour of the vehicle. These alternative monitoring methods are now being implemented in a prototype unit to be tested on the metro Roma network.

1

H. Tsunashima, A. Matsumoto, T. Kojima, T. Mizuma, "Condition monitoring of railway tracks using in-service vehicles - Development of probe system for track condition monitoring", Japanese Railway Engineering, 161, 6-10, 2008.

2

P. Belforte, F. Cheli, R. Corradi, A. Facchinetti, "Software for the Numerical Simulation of Tramcar Vehicle Dynamics", International Journal of Heavy Vehicle Systems, 10(1-2), 48-69, 2003. doi:10.1504/IJHVS.2003.002434

3

F. Cheli, R. Corradi, G. Diana, A. Facchinetti, "Validation of a numerical model for the simulation of tramcar vehicle dynamics by means of comparison with experimental data", Journal of Computational and Nonlinear Dynamics, 2(4), 299-307, 2007. doi:10.1115/1.2754306

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £110 +P&P)