Project Profile: Midland Main Line (MML) Upgrade

The Midland Main Line Upgrade is a multi-billion-pound railway enhancement project in the United Kingdom, focused on electrifying and increasing the capacity of the key route connecting London with the East Midlands and Yorkshire. This profile details the project’s extensive infrastructure works, including track doubling, bridge reconstructions, and the installation of a 25 kV AC overhead line system designed to improve journey times and decarbonise services.

Project Fact Sheet

Technical Specifications

The core of the upgrade is the deployment of a 25 kV AC Overhead Line Electrification (OLE) system. This necessitated installing over 12,500 OLE structures and components, powered via four national grid connections and distributed through 24 newly constructed substations to ensure consistent traction power. The system is designed to power new electric and bi-mode rolling stock, reducing reliance on diesel traction.

Significant civil engineering works were required to achieve the necessary vertical clearance for the OLE. This undertaking included the complete reconstruction of 13 overbridges and extensive modifications to tunnels and other lineside structures. The project also involved major track and formation improvements, notably the addition of a fourth track along the 23 km section between Kettering and Corby to eliminate a key capacity bottleneck.

The infrastructure upgrade is complemented by the introduction of modern signalling systems compatible with electric operations, enhancing safety and operational flexibility. Electrification facilitates the use of Class 810 ‘Aurora’ bi-mode multiple units (BMUs), which operate on electric power where available and seamlessly switch to diesel engines for non-electrified northern sections of the route.

Key Takeaways

• Decarbonisation and Sustainability: The project shifts a major inter-city route from diesel to electric traction for its southern section, significantly reducing carbon emissions and local air pollutants in line with UK environmental targets.
• Capacity and Performance: The addition of a fourth track on a critical section, combined with upgraded signalling, increases line capacity, enabling more frequent services (up to six trains per hour) and reducing journey times between London and key East Midlands cities.
• Economic Enablement: By enhancing connectivity for passengers and freight, the upgrade supports economic growth across the East Midlands by providing faster, more reliable, and higher-capacity transport links to the capital.

Frequently Asked Questions (FAQ)

When will the Midland Main Line upgrade be fully complete?

The southern section of the Midland Main Line upgrade, providing electric services to Kettering and Corby, is fully operational. Full electrification to Leicester, Derby, Nottingham, and Sheffield is currently not scheduled, with future phases subject to government funding and the proposals outlined in the national Integrated Rail Plan.

Who is building the Midland Main Line upgrade?

The Midland Main Line upgrade is owned and managed by Network Rail. Key delivery partners have included the design and engineering consultancy Atkins and the specialist contractor SPL Powerlines for the installation of the overhead line electrification system. The construction firm Carillion was also a major contractor before it ceased trading.