Project Case Study: Agar Grove Overbridge Renewal and Headspan Renewals

Client/Organisation: Bam Nuttal

Project Duration: January 2022 to December 2025

Project Design Value: OLE = £160k, Surveys = £20k

Project Implementation: £30m

Background:
The Agar Grove overbridge had become structurally unsound due to age. Its replacement was essential not only for safety, but also to maintain reliable rail operation on the Midland Main Line below. The railway consists of 7 electrified tracks under the bridge, with 35 no. OLE supports to the bridge itself. The carefully planned December 2024 blockade allowed a complete demolition and rebuild in just nine days, minimising disruption and supporting long‑term infrastructure resilience.

Objectives:
To provide Bam Nuttal and wider construction teams with the necessary technical drawings to successfully remove and re-instate the overhead line equipment to the new bridge, together with staged drawings to allow the lowering and lifting of the OLE.

The project included the requirement for:-

• Geometry assessments of the OLE
• All relevant technical drawings for construction purposes
• Attendance at numerous technically challenging inter-disciplinary meetings
• Renewal design of 17 headspans and 27 cantilevers in the vicinity of the overbridge
• Renewal design of 4 no. SI’s in the vicinity of the overbridge.
• On call site support during the construction works

Scope of Work:
Our scope was to provide the following:-

• OLE Lowering design, to enable the safe demolition of the overbridge
• OLE Clearance designs to enable the installation of a temporary pedestrian footbridge for cicra. 12 months.
• OLE design for the temporary re-routing of the IRC to allow installation of the footbridge, and re-instatement design to the new bridge.
• Various OLE bonding designs to support the installation of temporary and permanent lineside equipment and scaffolds.
• OLE design for the new overbridge including all supporting material requirements and clearance information, including rationalisation of the existing bonding arrangement.
• OLE design for the replacement of 17 headspans in close proximity to Agar Grove
• OLE design for the replacement of 27 cantilevers in close proximity to Agar Grove
• Renewal of 4 no. Section Insulators within the footprint of the overbridge.

Team Involved:

Surveys
Matt Chilton – Survey Director

OLE
Warren Bain – OLE CRE
Simon Williams – Lead OLE Designer
Elliott Robinson – OLE Engineer

Challenges:
Key Challenges on the project were:-

• Interfacing between all disciplines to improve the electrical clearances through design of bridge structure, road gradients, utility requirements, and steelwork design.
• Responding to additional scope requirements to fully utilise the OLE construction resource during the 9-day blockade – this led to the addition of 17 headspan renewal designs, 27 cantilevers and 5 small core insulator replacements.
• Ensuring all designs were successfully and issued for construction during the 9 day blockade, for which handback to an operational railway was essential.
• Ensuring all materials, including contingency materials were available on site to complete the works within the 9 day window.

Key Achievements:
All milestones for our survey and design deliverables were met enabling the timely interface with all other disciplines allowing issue of the AFC design and successful installation during the 9-day blockade. Handback on time with all planned OLE works completed in full.

Technologies Used (if applicable):
Bentley MicroStation (OLE Design)
Pointcloud Scans (Survey)

Results:
Providing all our deliverables to programme enabled the project to progress as required and meet the desired output. Our flexibility to meet the challenging demands of additional scope requirements on this project was fully appreciated by the client and Network Rail. The success of the OLE works with the 9-day blockade meant minimal follow-up snagging shifts and allowed the railway to open to electric traffic on time.