The sea cliffs up to 50 metres high extending 5.5km between Dawlish and Teignmouth have presented a substantial risk to the railway since it was constructed over 100 years ago. Rockfall, slabslides and the potential for large scale geological failure have necessitated a multiphase programme for stabilisation of the cliffs and/or protection of the railway.

TGP has evaluated the requirement for the protection of the railway using a risk based approach for the various sections of cliffs along the 5.5km stretch. This approach adopts the philosophy set out in Network Rail’s Safety case that remediation must demonstrate a Net Safety Benefit to justify the remediation cost. A risk analysis model has been used which adopts parameters from Network Rail’s risk model and examines a series of additional parameters specific to the particular site such as train frequency, derailment consequence (including head on collision), local topography and factors in the effectiveness of the remediation in reducing risks from different geologic al events.

Rockfall fencing and a debris barrier were installed in early 2003 along the toe of the cliff and the system has been designed to resist potential rockfall that may occur during the remediation work to the cliffs that followed or for the foreseeable future for those areas where no further remediation was planned. Areas of the cliff were selected for remediation based on expert qualitative review of the geology by site inspection, aerial photographs, topography, vegetation and historical information. These selected areas were then netted or stabilised using a combination of non-metallic nails, drainage netting and matting, with the fence acting as an integral part of the overall protection scheme.