- Water
- 17 Dec 2025
As part of the Caledonia Water Alliance (CWA), a joint venture between M Group Water and AECOM, we’ve successfully tunnelled under the main Glasgow to Stirling railway line and M9.
Working with Pipeline Drillers, the tunnelling has allowed for the completion of a key phase of a £13m Scottish Water project to support new housing in Stirlingshire.
Two pipes are being installed across 2.5 miles of land between Plean and Cowie to carry pressurised waste water for treatment.
Steven Greenhill, Scottish Water Alliance Team Manager, said: “This is an important project addressing one of our key strategic priorities to meet the demands of Scotland’s growing and shifting population.
“The new pipes will carry pressurised waste water from Plean to Cowie, supporting new housing being built in the area. The twin challenges of drilling underneath both the motorway and railway line required a co-ordinated multi-agency approach to avoid causing major disruption. We are grateful to all involved for their help and support and I am particularly pleased tunnelling operations have been successfully completed”.
Two different methods were deployed to install the pipes beneath the motorway and the railway.
Firstly, for the M9, pipe ramming was used, where a pneumatic hammer drives the steel casing into the ground, displacing soil which is later removed from inside the casing.
Due to the harder ground and greater depth required under the railway, rock augur drilling was deployed where a pneumatic cutting head bores through the soil and rock.
Richard Patterson, CWA Project Manager, added: ‘This remains a key project in the CWA capital programme, the integrated project team have successfully designed, planned and executed some of the complex engineering works required to date. Progress remains on track to reach completion in summer 2026 to deliver the wider benefit to the local environment.”
