2018
SEATON - DEVON - United Kingdom
Seaton Tramway
Kimber Contracting Ltd
BSW Consulting Engineers
Seaton Tramway Station Embankment Stabilisation
SEATION TRAMWAY
ParaLink® being laid as basal reinforcement over CMCs
TerraMesh™ system placed over ParaLink®
View of the developing TerraMesh™ embankment
MacGrid EG L used as ballast reinforcement
Top of TerraMesh™ system unit used also as ballast reinforcement
Challenge
Seaton, a large seaside town in Devon, is well known as a popular tourist destination, offering scenic coastal views and attractions such as the historic Seaton Tramway. This narrow-gauge electric tramway, measuring 2 ft 9 in (838 mm), follows part of a former London & South Western Railway branch line and runs for three miles through the unspoilt countryside of the Axe Valley.
In recent years, Seaton has undergone a significant regeneration programme that has enhanced its appeal and infrastructure. Developments have included the construction of major retail and hospitality facilities such as a Tesco store and a Premier Inn, along with more than 200 new homes built by Bovis. A key feature of this regeneration was the creation of a modern, state-of-the-art tramway station, which opened in June 2018.
As one of the first new stations to be constructed on a heritage railway site in decades, the project introduced a range of complex engineering challenges not encountered since the 1970s. The station development also incorporated additional amenities, including a café and gift shop named in honour of the tramway’s founder, Claude Lane. However, the site presented significant constraints: the station platform was elevated approximately two metres above ground level, and the available working area was extremely limited. These factors, combined with the need to construct a stable tramway embankment within a confined footprint, required a carefully engineered reinforcement solution.
Solution
The project site was located above soft ground conditions, which necessitated substantial ground improvement measures to ensure long-term stability. To address this, the platform area adjacent to the new terminus building was treated using Controlled Modulus Columns (CMCs), providing enhanced load-bearing capacity. In addition, retaining structures were required along the edges of the embankments, which reached heights of up to 2.5 metres.
Operational requirements further influenced the design. The trams impose a total load of approximately 160 kN across the track width, and additional loads arise from overhead electrical line equipment used to power the system. These combined effects were modelled as a variable surcharge load of 30 kPa applied across the crest of the embankment.
To meet these challenges, Maccaferri developed a tailored solution incorporating high-performance geosynthetics and modular retaining systems. A basal reinforcement layer of Paralink high-strength geogrid was specified to control differential settlement and enhance overall embankment stability. Detailed design analysis confirmed that a single layer of Paralink 1200, installed perpendicular to the embankment centreline, was sufficient to achieve the required performance.
To form the retaining walls, the Terramesh System was utilised, providing a flexible and robust structure suitable for the constrained site conditions. In addition, Macgrid EG L biaxial extruded geogrids were incorporated within the ballast layers to provide supplementary reinforcement and improve load distribution.
Together, these solutions delivered a stable, efficient, and constructible embankment system capable of supporting both the operational loads of the tramway and the spatial constraints of the site, while aligning with the aesthetic and functional requirements of this landmark regeneration project.
Used Products
