What is rail electrification?

Rail electrification is the process of enabling electric trains to run on railways tracks. This allows rail network providers to phase out engines powered by diesel. 

Why is railway electrification important? 

Electrifying the railway network offers several benefits:

•    Reduces reliance on diesel-powered locomotives and multiple units.
•    Lowers greenhouse gas emissions and improves air quality.
•    Improves energy efficiency across the rail network.
•    Supports the transition to renewable energy sources.
•    Reduces long-term operating and maintenance costs.
•    Increases train performance, acceleration, and reliability.

Where electricity is generated from renewable sources such as wind, solar, or hydroelectric power, the overall environmental impact of rail transport can be significantly reduced.

The process of rail electrification has been underway in the UK for several years, but it requires labour-intensive trackside works that take significant periods of time. Even though elements of the network (such as the London Underground) have been electrified since 1890 to avoid fumes in the underground tunnels, the modern push for electrification is centred more on the need to reduce operating costs and the carbon footprint of the rail network by switching to more renewable and efficient energy sources. 

What types of railway electrification systems are used?

Several methods are used to deliver electrical power to trains.
Overhead Line Equipment (OLE or OHL) is the most widely used rail electrification system worldwide and is the preferred solution for many modern railway projects, and by Network Rail, the owners of the UK track network.

This overhead line system consists of:

•    Contact wire carrying electrical current.
•    Catenary wires and flexible conductors that support the contact system.
•    Supporting structures, masts, and associated hardware.
•    High voltage and bare Aluminium feeder cables, providing power to the other elements.

Electric current is collected by a pantograph mounted on the roof of the train, which maintains continuous contact with the overhead contact wire while travelling.

Other less conventional methods include:

Third rail electrification: a power supply system that uses an additional electrified conductor rail installed alongside the running rails to provide electricity directly to trains. More in our detailed FAQ page.

Fourth rail systems: similar to Third rail, this system uses two additional rails for delivering power, one negative and one positive and it’s often used in underground environments.