Lower-carbon track for south London railway
Network Rail has replaced just over a kilometre of plain line track using low-carbon, sustainable materials.
Aerial view of track between Honor Oak Park and Brockley looking nort
© Network RailThe project was led by Network's Rail Southern Renewals Enterprise (SRE), with VolkerRail renewing track between Honor Oak Park and Forest Hill using innovative products.
The rail body says that track was fully welded, stressed and handed back early at line speed.
Materials account for as much as 90% of the overall carbon footprint in track renewals, Network Rail says, mainly from steel rails, concrete sleepers and ballast.
This section included:
- Green steel rail - produced using an electric arc furnace, achieving around 60% lower carbon intensity compared with traditional blast furnace steel.
- Low-carbon concrete sleepers - designed to deliver an estimated 40% reduction in embodied carbon.
- Recycled blended ballast - achieving up to 13% carbon savings by reducing the need for virgin aggregate.
- ISCC-certified renewable biofuel (commonly referred to as HVO)
- Solar-powered welfare units - reducing the need for diesel generators and cutting on-site emissions.
Network Rail says it is the first time three primary track components of rail, sleepers and ballast have achieved verified carbon reductrions on a single rail in the south of England, while also using HVO-fuelled trains.
The combination avoided 581tCO2e, or 63%, compared with baseline materials and transport emissions - the equivalent of ~200 UK households.
Network Rail also reports that from April 2024 to April 2025, the SRE reduced whole-life carbon against the baseline by 10.2%.
