Monitoring techniques and methods need to align with the demand for safe and efficient infrastructure in the railway network, write E Alexandra Micu, Eugene O'Brien, Cathal Bowe and Vikram PakrashiIreland is one such example and has a continuing programme of monitoring the infrastructure, with safety as the highest priority.

SmartBridge project

A recent Science Foundation Ireland (SFI) funded Industry fellowship (19/IFA/7433) involving University College Dublin and Iarnród Éireann is investigating the potential of using instrumented trains to monitor structural changes such as damage in bridges. Aptly named SmartBridge, the project aims to demonstrate the use of instrumented vehicles for anomaly detection related to damage or repair.

As a proof of concept around such an idea, the 2009 collapse of the two spans of the Malahide viaduct (Figure 1), due to foundation scour, is considered. While the incident did not result in causalities, it caused significant traffic disruptions on the Dublin-Belfast railway line.

The repair works lasted for about three months, having a significant impact for the travelling public and costs for the network owner. The layout plan and the upside elevation of the railway bridge after repairs are illustrated in Figure 2.

Figure 1. Malahide viaduct bridge collapse(1)

Figure 2. Malahide viaduct (UBB30) – elevation and layout plan

It is well established in the literature that the dynamic response of rail infrastructure to loading influences the behaviour of the moving rolling stock(2, 3), ie, the passing of the train causes the bridge to vibrate which, in turn, causes the train to vibrate.

In this regard, the project recently investigated data obtained from a train instrumented with accelerometers(4), which collected vibration responses on the Dublin-Belfast railway line.

This showed how vibration in the train was influenced by repair of some spans of the bridge. The general architecture of the monitoring system, installed on an intercity train, is presented in Figure 3.

Figure 3. General instrumentation arrangement

Samples of the vertical acceleration signals are displayed in Figure 4, as a function of distance, for multiple train runs over the Malahide viaduct. Lower amplitude signals are clearly visible at about 15.4km, where the pier and the beams on two spans were replaced after the 2009 collapse.

The signal follows the same pattern from run to run and the differences between the old spans and the new ones are considerable. The researchers have now identified small differences in foundation stiffness beneath each pier, after a detailed analysis of the signal and the structure dimensions(5).

Figure 4. Bogie Vertical Acceleration for multiple train passes over the Malahide viaduct

This SmartBridge success enables future implementation of the train as a moving probe for rapid assessment of condition and repair needs on bridges(6). This is of relevance for demonstrating rehabilitation efficacy(7), extending the information that is typically found from regular inspections(8).

The full-scale demonstration nature of the work could provide confidence for infrastructure owners worldwide to adopt such on-board systems for structural health monitoring of their infrastructure assets(9).

The extension of this solution to the entire network offers the potential for railway infrastructure owners to achieve more accurate and robust forecasts of maintenance requirements and future infrastructure condition. The work also demonstrates how such historic big data can be exploited and interpreted in a useful fashion for the end user.

SmartBridge, via Dr Micu, is currently working to create more complex monitoring systems with instrumented trains in collaboration with the EU Interreg project, Strengthening Infrastructure Risk Assessment in the Atlantic Area (SIRMA, EAPA_826/2018).

It is expected that this will be installed on an in-service train in Ireland in 2021 for continuous monitoring of the railway network(10).

Collected data will have the potential to provide information on railway system health such as bearing condition, wheel flats, settlement or loss of track stiffness, rail defects, bridge scour etc, and will assist the network manager with maintenance decisions.

The work will also emphasise the value of such industry-academic partnership, along with demonstration benchmarks(11) that they can create for stronger and resilient(12) infrastructure systems.

(Acknowledgement: Science Foundation Ireland (SFI) funded Industry Fellowship (19/IFA/7433), SIRMA, EAPA_826/2018 and Science Foundation Ireland MaREI Centre (12/RC/2302_2). For the purpose of Open Access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission.)

Authors: E. Alexandra Micu1,2, Eugene O'Brien3, Cathal Bowe4 and Vikram Pakrashi1,2

  • 1 Dynamical Systems and Risk Laboratory, School of Mechanical and Materials Engineering, University College Dublin, Ireland
  • 2 Science Foundation Ireland (SFI) Research Centre for Energy, Climate and Marine, University College Dublin Ireland
  • 3 School of Civil Engineering, University College Dublin, Ireland
  • 4 Iarnród Éireann, Ireland


1.) Gavin, Kenneth, Luke J Prendergast, Irina Stipanovič, and Sandra Škarič. "Recent development and remaining challenges in determining unique bridge scour performance indicators." The Baltic Journal of Road and Bridge Engineering 13, no. 3 (2018): 291-300.

2.) Karis T Correlation between Track Irregularities and Vehicle Dynamic Response Based on Measurements and Simulations: KTH Royal Institute of Technology; 2018, PhD Thesis.

3.) Majka M, Hartnett M Dynamic response of bridges to moving trains: A study on effects of random track irregularities and bridge skewness. Computers & Structures. 2009;87(19-20):1233-52.

4.) Quirke P Drive-by detection of railway track longitudinal profile, stiffness and bridge damage. School of Civil Engineering; University College Dublin: Ireland, 2017, PhD Thesis.

5.) Fitzgerald PC, Malekjafarian A, Bhowmik B, Prendergast LJ, Cahill P, Kim C-W, et al. Scour damage detection and structural health monitoring of a laboratory-scaled bridge using a vibration energy harvesting device. Sensors. 2019;19(11):2572.

6.) Khan MA, McCrum D, O'Brien EJ, Bowe C, Hester D, McGetrick PJ, et al. Re-deployable Sensors for Modal Estimates of Bridges and Detection of Damage-Induced Changes in Boundary Conditions. Struct Infrastruct E. 2021. DOI: 10.1080/15732479.2021.1887292.

7.) Pakrashi, V, Harkin, J, Kelly, J, Farrell, A and Nanukuttan, S, 2013, March. Monitoring and repair of an impact damaged prestressed bridge. In Proceedings of the Institution of Civil Engineers-Bridge Engineering (Vol. 166, No. 1, pp. 16-29). Thomas Telford Ltd.

8.) Quirk L, Matos J, Murphy J, Pakrashi V Visual inspection and bridge management. Struct Infrastruct E. 2018;14(3):320-32.

9.) O'Donnell, D, Wright, R, O'Byrne, M, Sadhu, A, Edwards Murphy, F, Cahill, P, Kelliher, D, Ghosh, B, Schoefs, F, Mathewson, A and Popovici, E, 2017, June. Modelling and testing of a historic steel suspension footbridge in Ireland. In Proceedings of the Institution of Civil Engineers-Bridge Engineering, 170(2), 116-132.

10.) Pakrashi V, Chawla R, Hester D, Micu A and O'Brien EJ. Instrumented Trains as a Probe for Structural Health Monitoring of Railway Infrastructure. (2020). Civil Engineering Research in Ireland 2020 (CERI2020) and Irish Transportation Research Network 2020, 297-299 (ITRN2020) Conference, Cork Institute of Technology, Ireland (held online due to Covid19).

11.) Cahill P, Hazra B, Karoumi R, Mathewson A, Pakrashi V Vibration energy harvesting based monitoring of an operational bridge undergoing forced vibration and train passage. Mech Syst Signal Pr. 2018;106:265-83.

12.) Martinez-Pastor B, V P Transport networks: Being resilient and change ready. EngineersJournalie. 2020;