We are delighted to share that the South Rail Systems Alliance (SRSA) have successfully completed the major commissioning of the Poplar Rail Lines electrification project, strengthening the resilience of the Western and Anglia networks.
The SRSA and Colas Rail UK’s Infrastructure division have delivered electrification from Acton West Junction along both the Up and Down Poplar lines, a demonstration of our ability to energise a newly electrified route for the first time, bringing benefits to all railway users.
This includes diversionary routes for passengers for future track possessions for the Old Oak Common (OOC) High Speed 2 (HS2) station and mitigates any impact on the local Elizabeth Line depot completing maintenance on their fleet.
Poplars Project Scope
The main duties performed by our team were the installations of:
Incorporating our in-house expertise, we also completed other infrastructure upgrades including Overhead Line (OLE) and Signalling & Telecoms (S&T) on the Up and Down Main Lines.
- Overhead line equipment (OLE), including new structures and foundations
- New and modified wire runs
- New electrical sections controlled by a blend of motorised and manual switches
- A neutral section
- Signalling alterations and updates
- Upgrade to existing bonding arrangements and cable routes
- Installation of new safety and operational signage
- Upgrade to platform fencing at Acton Mainline Station
Other upgrades include software and interface changes at the Rugby and Didcot control centres. The upgrades will also improve depot access for maintenance of the Elizabeth Line fleet and contribute to Network Rail’s decarbonisation strategy to allow for sustainable electric trains to run on this section of the network and between the North London Line and Great Western Main Line (GWML).
The Anglia side of the network was energised in early November 2025, while the Western side received their power upgrades on the 27th of December delivered in conjunction with the SRSA’s OOC Christmas blockade.
Full operational capability expected by Easter 2026, where these upgrades will link to the existing electrified sections at Acton Wells junction, connecting with the Acton Willesden Line and the Barking to Gospel Oak Line.
Old Oak Common Team Renew Rail Systems
In conjunction to the Poplar electrification programme, the SRSA also delivered further rail systems upgrades to the GWML at OOC as part of the new HS2 interchange station.
During the two-day blockade, the team installed a new four-line Under Track Crossing (UTX) to a depth of 2.5 m, one of 24 UTXs being delivered as part of the cable management strategy for the upgraded power and signalling systems. These works will provide a new temporary route for the GWML while OOC station enters the next phase of its construction programme.
OLE construction was also undertaken, including the conversion of an existing balance weight system to a state-of-the-art Tensorex C+ system and the installation of new OLE structures and Small Parts Steelwork, enabling wires to be easily transferred to the new equipment and OLE headspan structures to be removed. These changes increase the reliability, resilience and efficiency of the overhead line system and significantly reducing the impact of failures caused by legacy equipment.
Speaking about the success of the schemes, Network Rail Sponsor, Gavin Cambridge said “SRSA have been critical to the success of the Poplars Electrification project, helping to progress the scheme from project inception through to energisation in less than three years.
“Throughout this time SRSA have worked diligently alongside Network Rail to develop a solution and the programme to deliver it, overcoming engineering and delivery challenges along the way. The final energisation works at Christmas were the culmination of this hard work, delivering a Network Rail national milestone with minimal disruption to the travelling public.”
All works were completed successfully and with support from our trusted supply chain.
The SRSA’s On Network Works is a partnership between Colas Rail, AECOM and Network Rail, an alliance delivering the rail systems for the new OOC station.
First published: 3rd February 2026