ACO Water Management provided a complete surface water management solution at Network Rail’s Three Bridges railway maintenance depot near Crawley. By utilising products from its permanent way and rail infrastructure range, ACO was able to meet the project’s specification and help overcome challenging on-site logistics.
The new rail depot is part of the Thameslink rolling stock project, which is an initiative to provide additional passenger capacity and remove bottlenecks on the London commuter network. The development is split into east and west side facilities and, among other buildings, includes a five-road, 12-car train care building, two carriage washing machines and an under-frame jet wash. The project is led by Siemens, with Hyder Consulting as the consulting engineer working for main contractor Volker Fitzpatrick.
The project required two stormwater attenuation tanks to meet site hydraulic requirements. The tanks collected flows from the shed roofs and highways. In addition, the project required a series of drainage channels to collect trade effluent flows from maintenance building services pits, train wash facilities and track in front of buildings; these flows then went to the sewer. Adding to the complexity was a low bridge that restricted access to the site, with larger delivery vehicles not able to pass underneath.
Two ACO StormBrixx tanks, of 1150m3 and 370m3 volume, were integral to the surface water solution. The unique geocellular stormwater management system is designed to stack for shipment, saving space and keeping transport costs to a minimum. With smaller delivery vehicles required to reach the Three Bridges site, this meant deliveries were minimised – ACO StormBrixx was supplied using around 75% less deliveries than would have been required for comparative tanks.
The system also benefits from a patented cell brick and cross bonding feature that speeds up installation time because it is stackable; meaning the installer, Environmental Construction Solutions Ltd, was able to deliver on the exceptionally tight, six day installation deadline.
The system will work in conjunction with ACO Q-Brake Vortex controllers to manage surface water run-off and control the rate of discharge into a local watercourse. The design of the ACO Q-Brake Vortex is based on the fluid mechanics principle of the forced vortex, which permits regulation without any moving parts – and it is fitted with an integral bypass door that can be opened in the event of a blockage.
With the ACO StormBrixx’s open cell structure permitting completely free access for CCTV and jetting equipment – meaning it can be inspected and maintained from just a few access points – the system offers Network Rail an easy to maintain solution.