The South Rail Systems Alliance (SRSA) has successfully completed the required infrastructure upgrades on the West Anglia main line to support the future rail services for Cambridge South station.
Appointed in September 2023, SRSA (comprised of Colas Rail UK, Network Rail and AECOM) has delivered a range of major infrastructure upgrades between Shepreth and Cambridge as part of a multidisciplinary programme working alongside station contractor, Murphy and signalling partner, Alstom. These include:
- Renewal of 5.7km of track between Shepreth and Cambridge and realignment of 1.4km of track to serve the new four-platform station
- Installation of eight new switches which allow trains to switch from one track to another.
- Upgrades of the overhead line electrification (OLE) consisting of 110 new foundations to support 79 new OLE structures, and almost 10km of new overhead wiring.
- Installation of eight new signals
- Remodelling of Shepreth branch junction to unlock higher train speeds through the junction.
- Upgrades to ancillary systems such as communications, telecoms and power supplies
All of this work has been safely delivered by Colas Rail UK staff and its supply chain with 124,000 site staff hours completed over 10,000 working shifts with no major accidents or incidents.
The key milestones for the project including the 2023 Christmas blockade when the existing main lines were diverted onto two new alignments to facilitate the construction of the station platforms.
Key weekend dates in May and June 2024 saw SRSA install new switches and crossings which allow trains to change between tracks, while modifications were made to the overhead lines to maintain power supplies to train services along the new track alignment.
Christmas 2024 saw SRSA undertake a successful remodelling of Shepreth branch junction while the railway was closed for almost two weeks. The modified junction has been made longer, reducing the curve radius which makes it more efficient for train services to navigate the junction at increased speeds.
This will enable train services to travel through the junction at the line speed of 50mph (instead of 30mph) once the signalling upgrades have been completed anticipated for the end of 2025.
The Christmas 2024 work also included the connections of two new tracks onto their final alignments through the station, making Cambridge South a four track/platform station.
As part of its social value contribution to the local community, SRSA has joined forces with with the local authority’s environmental team to undertake volunteering days. This included managing local vegetation, removing litter and installing new fencing for a local nature reserve, to positively contribute to the community.
Richard Flanagan, Project Director for SRSA and Colas Rail UK Enhancements said: “The completion of our works over the Christmas 2024 blockade brings a close to the track systems works we have undertaken over the last 18 months at Cambridge South.
“I am delighted with the progress we made at each key stage of the project. Safely delivering our full scope whilst meeting our programme milestones. Safety is our number one priority, to support our safety culture as a team we embrace new innovative technology, Geofencing and tagging supplements enhances our safety systems by adding an additional layer of protection. Its simplicity and ease of use has enabled Colas Rail UK and the SRSA to engage with the workforce and roll out seamlessly.”
Kevin Sullivan, Programme Manager for Network Rail said: “The safe and successful completion of the rail systems by SRSA is a major milestone in the journey to deliver this brand new station for the south of Cambridge, the neighbouring biomedical campus and Trumpington communities.
“Their commitment and drive to complete this work safely is a testament to their dedication and professionalism and this work has highlighted how well we can work together to improve and upgrade the railway for our customers and our passengers.”
The station is due to open in 2026.
First published: 16th May 2025