WP1

Monitoring and Inspection

The current methods of track inspection for the railway networks considered within this project consist largely of visual inspection techniques. The benefits of such an approach are obvious in that trained inspectors and engineers develop intimate knowledge of the visual condition of existing infrastructure and in some cases (e.g. where drainage channels have become blocked) can organise fast remedial works. A further advantage is that it is cost effective as the inspectors are typically employees of the network operator. Direct investigations which for example include geotechnical or geophysical techniques to investigate earthworks are used mostly in the forensic examination of failure³. Disadvantages of visual inspections are:

• Safety – visual inspections involve staff walking on usually live railway lines,
• Continuity – when experienced staff retire, their knowledge is lost. This was identified as a key factor in the public enquiry of the Malahide Viaduct failure in Ireland, which found that the engineer who performed the critical visual inspection did not in fact have vital information on how the structure maintained stability, and most importantly

A visual inspection of a slope, tunnel or bridge will not reveal whether some deep-seated mechanism such as a weak soil layer, reinforcement corrosion in concrete or scour beneath a foundation in a river is likely to result in imminent catastrophic failure. For these reasons it is vital that reliable means of providing real-time information on critical sections of infrastructure are deployed.

• Network of embedded sensors
• Instrumented slope
• NDT testing to investigate slopes
• Identifying bridge scour