Challenge
A rail cutting near Pembroke in South Wales required trackside drainage as part of broader renewal works. Shallow bedrock severely restricted excavation depth, while existing telecoms infrastructure further limited layout options and routing possibilities. The curved, uneven terrain demanded a drainage route that could follow complex topography. Tight rail possession windows required rapid, efficient installation with no margin for delay.
Solution
The Rosehill Drainage System — comprising Trough & Stacker components with Drainage Mats — was installed along the cutting at a precise 1:20 longitudinal gradient. Units were cut and stepped on site to follow the terrain while maintaining complete flow continuity. A 75mm compacted pea gravel bed provided a stable, well-draining support base, and 50mm Drainage Mats were strategically positioned to protect the trough from sediment build-up. The modular system adapted to ground constraints without compromising performance.
Result
The target discharge rate of 42 litres per second was successfully delivered. Installation was completed on time with no delays to the broader renewal programme, despite challenging ground conditions and infrastructure constraints. The system remained fully functional post-installation, demonstrating that modular drainage can overcome the site-specific challenges routinely encountered in rail environments.
- 1:20 longitudinal gradient precision
- Shallow bedrock installation
- Telecoms infrastructure navigated
- Tight rail possession compliance
- 75mm pea gravel foundation
- Cut-and-step without performance loss
