Project Title: Overbridge CMP2/1A ‘Greek Street’ Reconstruction

Client/Organisation: J Murphy & Sons Ltd.

Project Duration: October 2023 – March 2025

Project Design Value: £130K (PBH Value)

Project Implementation Value: TBC

Background:
Greek Street overbridge (CMP2/1A) carries the two-lane Greek Street Roundabout over the five-track electrified West Coast Main Line, in Stockport City Centre. The bridge is located just south of Stockport Railway Station on ELR: CMP2 at 294.181km (182miles 1425yards).

Due to the condition of the bridge, Network Rail identified that the bridge is understrength and should be replaced.

The bridge currently supports a large number of OLE bridge arm supports and ten wire runs for the five tracks including several crossovers.

Objectives:
The bridge is due to be demolished and reconstructed in staged blockades between Christmas 2024, Easter 2025 and August 2025.

The new bridge deck is proposed to be lower than the existing, and as such the OLE system beneath the bridge needed to be lowered to maximise electrical clearances as much as possible whilst maintaining a compliant contact wire height beneath the bridge.

There was also a requirement for the temporary lowering of the OLE beneath the bridge to ground level to suit the bridge demolition strategy. The OLE conductors required to be lowered, protected and covered with a temporary crash deck for the duration of the demolition works.

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

• OLE Site surveys
• PACE Engineering Stages 3, 4 and 5 OLE Design
• Provision of OLE CRE role to ensure interdisciplinary design development, design to support the complex construction strategy (demolition and reconstruction including temporary works) and assurance achieved with numerous designers involved.
• Integration of design deliverables for all disciplines.

Team Involved
Kester Witt – OLE DRE (Design)
William Hart – Lead OLE Design Engineer for the project
Jack Marshall – OLE Design Engineer
Mike Shemilt – Director (OLE)

Challenges
Key Challenges on the project were: –

• Interfacing with many different disciplines to ensure project requirements were met.
• Construction staging.
• Complex wiring arrangement beneath the bridge
• Maximising electrical clearances given the lower new bridge deck height

Design Solution
PBH developed a new design contact wire to enable contact and catenary to be lowered to achieve reinforced electrical clearances to the new, lower bridge deck.

• OLE design for staging of the works to include for separate temporary lowering design
• Renewal of bridge supports with F&F Resic bridge supports fixed to new bridge deck.
• New replacement Return Conductor supports
• New traction bonding arrangement

Key Achievements

• All milestones for our survey and design deliverables were met
• Leading discussions relating to OLE staging to support the Principal Contractors construction strategy and planning
• Detailing the proposed lowering strategy for the complex OLE arrangement beneath the bridge

Results
Successful ES3/4 & 5 designs for both permanent and temporary OLE arrangements beneath the bridge.