Pembroke Rail Cutting

Trackside Drainage in Challenging Ground Conditions

Project Overview

The Pembroke Rail Cutting project presented a complex drainage challenge that required innovative solutions and precise execution. Located in South Wales, this trackside drainage installation demonstrated the Rosehill Drainage System's capability to overcome significant ground conditions and infrastructure constraints while delivering exceptional performance.

Working as part of broader rail renewal works, the project required completion within tight rail possession windows, making efficiency and reliability critical factors in the solution design and installation process.

The Challenge

Shallow bedrock severely restricted excavation depth for traditional drainage solutions
Telecoms infrastructure presence further limited layout options and routing possibilities
Curved, uneven terrain required drainage route to follow complex topography
Tight rail possession windows as part of broader renewal works demanded rapid, efficient installation
Performance requirements needed to achieve target discharge rate of 42 litres per second

The Solution

Rosehill Drainage System installation along the cutting with precise 1:20 longitudinal gradient
On-site cutting and stepping of units while maintaining complete flow continuity
75mm compacted pea gravel bed provided stable, well-draining support base
50mm Rosehill Drainage Mats strategically positioned to protect trough from sediment build-up
Modular system flexibility allowed adaptation to ground constraints without performance compromise

Litres per second
target achieved

1:20

Longitudinal gradient
precision installed

100%

Performance maintained
after cutting/stepping

On-time completion
within possession

Results

Target discharge rate achieved: 42 litres per second flow capacity successfully delivered
Constraint adaptation: Successfully navigated ground and infrastructure limitations
Schedule compliance: Installation completed on time with no delays to broader renewal works
Performance integrity: No compromise to hydraulic performance despite complex installation requirements
Operational success: System remained fully functional and effective post-installation

The Rosehill Drainage System proved how the system can overcome challenges we encounter on site regularly. The ability to cut and step the units without impacting the performance was extremely useful under a time-restricted install.

Bill Smalley

Construction Manager, Colas Rail UK