A national assessment of landslide hazard from Outside Party Slopes to the rail network of Great Britain

In recent years, a number of high profile landslide events have caused disruption, derailments or damage to railway infrastructure in Great Britain. A landslide susceptibility model of the entire railway network was created, designed to give a national overview of potential landslide hazard originating from Outside Party Slopes. The current assessment was compiled using Geographic Information System (GIS) techniques and desktop modelling to apply a structured analysis of each buffered Earthwork Inspection 5 Chain (c. 100 m; EI5C). Data analysed along the network included the BGS GeoSure instability model and newly updated national models for debris flow, earth flow and rock fall, supported by historical landslide data. In order to further focus the Outside Party Slope zone, a buffer of External Natural Geological Influence (BENGI) was created using a 5 m Digital Terrain Model. Landslide susceptibility for each EI5C was categorized using a ‘Classification of Hazards on Outside Party Slopes’ (CHOPS) score; representing the modelled potential for landslide hazard. The outputs were combined as a series of matrices to present the CHOPS and Network Rail Derailment Criticality Band interactions. This research will allow further focused analysis of the network, in order to prioritize and direct future investigation and policy decisions.