Network Rail has successfully completed a major £84 million upgrade to overhead line equipment (OLE) on the Midland Main Line between London St Pancras and Bedford — delivering the project on time and under budget.

The OLE125 Compatibility project, which ran from September 2023 to June 2025, replaced outdated infrastructure originally installed in the 1980s. The improvements now enable new bi-mode trains to operate at their optimum speeds, improving performance, reliability, and environmental efficiency on the route.

The upgrade was delivered in partnership with main contractor SPL Powerlines and included a wide range of infrastructure enhancements:


• 40 miles of railway upgraded

• 401 head spans replaced

• 108 wire runs upgraded

• 209 balance weight anchors modernised

• 636,618 working hours logged

• An average of 30 machines used per shift

As part of the works, routine maintenance was also carried out to make the most of track access periods, further enhancing the resilience of the line.

Paul Cater, Network Rail's Senior Portfolio Manager, said: "The successful OLE125 project has been about making the Midland Main Line more efficient and greener. This upgrade, combined with the wider electrification of the line, will mean the benefits are gained over a large area of our railway.

"We would like to thank everyone who helped us deliver the upgrades, which will have clear benefits for passengers as bi-mode trains can now run more efficiently between London and Bedford.

"We are also grateful to our neighbours living near the line for their patience while we worked on these major improvements and also maximised our time on track by carrying out many other maintenance tasks at the same time."