Project Name: Werrington Dive Under
Project Location: Cambridgeshire, England
High-speed passenger trains in shared corridors introduce new challenges in managing the existing capacity of railroad systems. When slower-moving freight trains need to cross these high-speed lanes, it can result in inconvenient and costly delays. Such was the case at Werrington Junction, located approximately five kilometers (3 miles) north of the Petersborough Rail Station.
A solution was required to increase the capacity for passenger trains on the East Coast Main Line. To accomplish this, a new two-track railway line was built under the existing line. Implemented by Network Rail, the Werrington Dive Under is part of a £1.2 billion ($1.6 billion) East Coast upgrade scheme. The new line will remove constraints to the train timetable caused by the slower freight trains on the Great North Great Eastern (GNGE) route, which currently have to cross over the high-speed East Coast Main Line.
Poor soil conditions with a CBR of 2% along the track route required a soil stabilization solution to improve undertrack stiffness. In addition to soft subgrade challenges, the project called for a system that would aid drainage and reduce the depth of excavation required for a traditional track installation. To meet these project requirements, Network Rail selected the GEOWEB® 3D Ballast Stabilization System.
Morgan Sindall Construction and Infrastructure carried out the project, which included the construction of 3 kilometers (1.9 miles) of new line with the GEOWEB system. The installation of an enhanced woven geotextile provided the ability to bridge soft spots with a CBR of less than 2% and prevent differential settlement. The woven geotextile also provides drainage, reinforcement, and filtration, which prevents fines from migrating up from the base and causing ballast fouling.
16,258 square meters (175,000 square feet) of the GEOWEB GW30v8 (200 mm) panels were installed and filled with crushed aggregate with a maximum size of 35 mm. The GEOWEB panels were secured with the patented ATRA® Keys. ATRA Keys provide a secure and permanent load-transfer connection and are three times stronger and three times faster to install than metal staples.
The Cost-Saving Benefits of the GEOWEB System for Rail Ballast Stabilization
The GEOWEB system stabilizes the ballast layer, reducing vertical and lateral stresses and significantly reducing subsoil movement. Stabilization within the system provides a longer-lasting track profile that extends rail service life while significantly reducing maintenance cycles and cost. The cost-benefit ratio is high because of its overall flexibility and low-cost installation rate. Long-term test results and successful applications worldwide confirm the benefits of the GEOWEB system.