It will start construction of the 209m long extension north of Parsons Tunnel in August.
Construction of the rockfall shelter is expected to take a year and, once complete, will help protect trains against falling rocks along this section of vital railway that connects communities across the south west with the rest of the country.
Parsons Tunnel was previously extended 100 years ago as a brick-built enclosed tunnel extension.
The new open-sided rockfall shelter will be constructed from a series of six-metre modular pre-cast concrete sections.
Faced with the challenging coastal location, Morgan Sindall has developed an innovative installation method to minimise the risk of weather-related disruption and reduce the impact on train services.
Peter Kirk, managing director of Morgan Sindall Infrastructure’s rail business unit, said: “We are excited to be working with Network Rail on their South West Rail Resilience Programme, and continuing to build on our long-standing partnership.
“Parsons Tunnel North Portal is an incredibly complex project and we are extremely pleased to bring a number of innovations to this project, helping to ensure the resilience of the railway line for the local community and those travelling to and from the area.”
This rockfall shelter, which is the third phase of work as part of Network Rail’s South West Rail Resilience Programme and follows the two sections of new sea wall in Dawlish built by BAM Nuttall.