Charlton West Cutting is located on the Avonmouth and Filton Railway line near Patchway, Bristol. CML was tasked with enhancing the current drainage system as part of Network Rail’s ‘Adverse Weather Programme’. The works involved renewing a 600m long drainage system positioned on a mid-slope bench of the cutting slope.
Charlton West Cutting is located on the Avonmouth and Filton Railway (AFR) near to Patchway, Bristol. The cutting is approximately 600m long and the slope is comprised of Mercia Mudstone with a mid-slope bench throughout. The existing drainage assets comprised an unlined mid-slope drainage ditch that ran from the high mileage end of Charlton Tunnel, to the syphon outfall which transfers water from the Up side to the Down side of the track via a UTX. The ditch was poorly maintained, overgrown and heavily silted with evidence of scour in places where the ditch had overtopped during heavy rainfall events putting the cutting slopes below at risk of wash-out.
As part of Network Rail’s ‘Adverse Weather Programme’, CML were commissioned to upgrade the existing drainage system, cutting a new drainage channel along the length of the mid-slope bench, lined with a HDPE trapezoidal ditch liner to create a leak-free system and regulate the flow of water along the varying gradients through the cutting. The new lined ditch was connected at the outfall into a syphon, which was cleared of debris and refurbished by installing new trash screens, including new stepped access systems to improve access for future maintenance.
All site clearance, de-vegetation, and new ditch construction works were safely completed during normal working hours with the railway remaining open under Any Line Open conditions. The jetting clear of the syphon was carried out by specialist road rail plant, verified by CCTV surveys, which was all undertaken during night time possessions to facilitate access.
Form G designs were produced during the build to accommodate instructions to design and install stepped access systems on both the up and down side of the cutting. A new inclined EA compliant trash screen with a level GRP access platform above was also installed to the inlet of the syphon.
This project was completed on programme, within budget, and with a very high quality finish.
Collaboration with local businesses and adjacent landowners was key to successfully managing the interface between our works and a new housing development project near to the track access point, to manage deconfliction of project activities. Regular liaison and coordination ensured no delays to either party, and minimised disruption to local residents.
These works were carried out during one of the wettest winters on record, presenting some very challenging working conditions in an already wet environment, so the site team were forced to think outside the box to control surface water flows safely during the installation of the new ditch system. The wet conditions also made the maintenance of a safe access and work platform particularly challenging in a constrained space. Nevertheless, the safety focused delivery team still managed to succesfully design and maintain separated walk routes to and from the work areas to mitigate the unfavourable underfoot conditions created by the adverse weather conditions.
Following a heavy rainfall event, a bank slip was identified in the cutting adjacent to the site of work. The line was immediately blocked to protect the railway, and our delivery team were able to respond, agreeing the design, and implementing a standard detail slope regrade using long reach plant to re-open the railway at full line speed within 36 hours.
Keep up to date with our latest news, projects and industry developments
© 2024 Construction Marine Ltd. All rights reserved.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.