Overhead line works

Overview

The North London Reinforcement (NLR) project will see work being conducted on the existing overhead line between Pelham substation and Hackney substation.

Overhead line (OHL) works are taking place on four different lines:

Locations	OHL name	Approximate length
Pelham – Rye House – Waltham Cross	4ZM	28.4 km
Brimsdown – Tottenham – Waltham Cross	ZBD	13.5 km
Brimsdown – Tottenham – Waltham Cross	ZBC	13.5 km
Tottenham – Hackney	VC	5.8 km

Traffic management

To ensure OHL upgrades are carried out safely, we are implementing strategic traffic management and road closures in some locations. Click here to learn more about our traffic management measures.

For the latest updates on work in these areas, click on the relevant location below:

Overhead lines upgrades
Substation upgrades

Timeline

Timings	OHL name	Location	Activity
March – July 2025	ZBD and ZBC	Between Waltham Cross and Tottenham Substation	Enabling works on overhead lines
March – September 2025	VC	Between Tottenham and Hackney substation	Enabling works on overhead lines
April – May 2025	All	Across the NLR line	Overhead line assessment
April – May 2025	4ZM	Between Pelham and Brimsdown substation	Enabling works on overhead lines
April – July 2025	ZBD and ZBC	Between Waltham Cross and Tottenham Substation	Planned outages on overhead lines
May – July 2025	4ZM	Between Pelham and Brimsdown substation	Planned outages on overhead lines
May – October 2025	4ZM	Between Pelham and Brimsdown substation	Reinstatement works
June – November 2025	ZBD and ZBC	Between Waltham Cross and Tottenham Substation	Reinstatement works
August – October 2025	VC	Between Tottenham and Hackney Substation	Planned outages on overhead lines
October – November 2025	VC	Between Tottenham and Hackney Substation	Reinstatement works

Pelham to Rye House

In your area, the 4ZM line will undergo enabling works near Hoddesford from 5 April to May 2025, which may result in traffic management measures. We will be sure to inform you of upcoming disruption as and when it is required. Preparation works including vegetation clearance are already underway, and teams will soon begin installing trackway to create temporary roadways designed to provide safe and stable access for vehicles, and equipment.

Between 15 May and 7 July 2025, we will be using SkySafe equipment to carry out works on the same line between Pelham and Waltham Cross requiring temporary bridleway closures off Hadham Road in Bishops Stortford and a byway closure off Fryars Lane near Sawbridegworth. Temporary diversions will be in place and the closures will be manned. SkySafe is a scaffold-less suspended wire system between pylons which allows engineers to work safely without causing disruption and is being used on major roads and areas where it is not possible to access the pylons through the usual method of netted scaffolding.

Reinstatement works, including trackway removal in Hoddesford and steelwork assessments at River Lee County Park, will take place from 16 May to 28 October 2025, with minimal disruption expected.

Rye House to Waltham Cross

In your area, we will be working on the 4ZM line between Rye House and Waltham Cross between 15 May and 20 June 2025, necessitating temporary footpath diversions of Dobbs Weir Road.

Reinstatement works, including steel structure replacements between Pelham and Brimsdown, will follow from 21 July to 12 September 2025, with minor delays anticipated during this period.

Waltham Cross to Brimsdown

In your area, we will carry out enabling works to the ZBD line near A121 Holdbrook South, Swan and Pike Road, and River Lee Country Park from March to 11 June 2025.

Preparation works including vegetation clearance are already underway, and teams will soon begin installing trackway to create temporary roadways designed to provide safe and stable access for vehicles, and equipment. Scaffolding will also be erected to provide stable and secure platforms for workers to perform maintenance tasks at height, ensuring that workers have safe access to all parts of the pylon or overhead line, reducing the risk of falls and accidents. Fencing and netting will also be placed to mark construction boundaries and to keep the public safe during works.

This may lead to footpath closures, and we will be sure to inform you of upcoming disruption as and when it is required.

SkySafe equipment will be used for works near Lee Valley Leisure Complex and Brancroft Way between 2 April and 26 June 2025, requiring temporary footpath closures off Prince of Wales open space. There will be diversions in place. SkySafe is a scaffold-less suspended wire system between pylons which allows engineers to work safely without causing disruption andis being used on major roads and areas where it is not possible to access the pylons through the usual method of netted scaffolding.Reinstatement activities, such as trackway and pontoon removal near William Girling Reservoir, and Swan and Pike Road, will run from 27 June to 4 August 2025.

Brimsdown to Tottenham

In your area, we will perform corrosion steelwork assessments on, and replacements to, the ZBC line between Brimsdown and Tottenham from 16 April to 5 November 2025. We expect there to be minimal disruption during this time. This will follow with reinstatement works to the ZBD line, including tower painting and muff replacements around the Lee Valley Leisure Centre and Towpath Road between 9 August and 21 November 2025. Intermittent footpath closures may occur during this phase., and we will be sure to inform you of any disruption as and when it is required.

Tottenham to Hackney

In your area, we are beginning enabling works to the VC line near Northumberland Park Bus Garage, Walthamstow Wetlands, and through Hackney Marshes from March to October 2025.

Preparation works including vegetation clearance are already underway, and teams will soon begin installing trackway to create temporary roadways designed to provide safe and stable access for vehicles, and equipment. Fencing and netting will also be placed to mark construction boundaries and to keep the public safe during works.

Between 20 August and 18 October 2025, we will be using SkySafe equipment near Lea Bridge Road and Hackney Marshes that will require footpath closures on the east side of Lee Valley Regional Park. SkySafe is a scaffold-less suspended wire system between pylons which allows engineers to work safely without causing disruption and is being used on major roads and areas where it is not possible to access the pylons through the usual method of netted scaffolding.

Reinstatement works such as trackway removal and tower painting near Coppermill Tower and Hackney Marshes will run from 19 October to 13 November 2025.