Design ID was appointed by FP McCann as temporary works design engineers for the refurbishment of the historic Downhill and Castlerock Tunnels, located beneath the National Trust’s Mussenden Temple on Ireland’s North Coast. The works involved repairing defective brickwork while maintaining railway operations, requiring carefully designed temporary works solutions.
Design ID developed and implemented temporary works solutions to facilitate the safe and efficient repair of the tunnels' masonry structure. The design ensured railway safety and protected the heritage value of the tunnels.
Key Technical Contributions
- Temporary steel and timber formwork: Designed a secure system to be fixed to the tunnel face during night-time railway possessions, ensuring clearances for operational trains.
- Retention lagging and steel supports: Provided stability for brickwork repairs while mortar cured, with bespoke steelwork shaped using laser surveys for precise fitting.
- Anchor testing: production of pull-out test specification to verify masonry anchors’ load-bearing capacity, reducing risk to railway infrastructure and preserving the tunnel’s aesthetics.
- Category 2 design check: Conducted an internal review process to add value and verify design integrity.
- Compliance and railway safety: Produced detailed drawings proving that the temporary works would remain in place without interfering with passing trains.
Regulatory and Compliance Aspects:
- Completion of Northern Ireland Railways Design and Check certification, Form C Certificate for Railway Temporary Works and achievement of Technical Approval from Northern Ireland Railways
Project Outcome
By delivering innovative temporary works solutions, Design ID supported the safe refurbishment of these historic railway tunnels while ensuring minimal disruption to rail services and preserving the site’s heritage.
Contractor: FP McCann
Client: Northern Ireland Railways
