Project overview 

An under‑track crossing (UTX), outside Woolston Station in Hampshire, had collapsed and renewal works were required to replace and upgrade the pipe, ensuring a safe, stable and properly drained railway. 

The UTX connects the drainage in the 6ft (the space between the tracks) to the drainage in the cess (the side of the track). It carries water collected from more than half a mile of railway drainage, moving it safely from the centre of the track to the side and then onwards to the final discharge point.

 

Objectives 

  • Conduct an initial investigation and site assessment 
  • Design a renewed UTX with a permanent drainage solution 
  • Install the renewed UTX and integrate with existing drainage assets to ensure continuous and effective flow

 

Scope of works 

Initial investigation 

An initial topographic survey was carried out to capture existing ground levels, drainage features and site constraints. The survey identified a backfall within the defective drainage and a suitable solution was developed and incorporated into the design to meet the overall requirements of the brief. 

Permanent works design 

OnSite Rail’s in-house design team developed a robust UTX drainage solution, linking the 6ft drainage to the cess system. The design incorporated a ductile iron pipe beneath the sleepers and ballast, with specified minimum cover depths to maintain track stability under loading. The pipe, encased in concrete, would ensure structural strength and longterm durability, in compliance with current National Rail standards for clearances, bedding, and ballast support. The layout would also allow access from both sides of the track for future inspection and maintenance, ensuring reliable drainage performance and safe operation of the railway. 

Installation of new UTX 

Works were delivered during a possession weekend and involved excavating the existing UTX and digging a trench to the required design depth in preparation for installing the new UTX pipe. All necessary track monitoring, both before and after the work, was carried out in accordance with the Track Monitoring Plan. In addition to the permanent works design, the in-house design team also produced the Form C for the Temporary Works required to deliver the scheme, liaising closely with the Principal Contractor and Network Rail throughout the development of the proposed solution. 

Integration of new UTX 

Rockers were installed at both the cess and the 6ft and then connected with the full length of pipe, after which the pipe levels and gradients were checked. Expansion joints were fitted over the connections between the rockers and the main pipe at each end. The pipe was then surrounded with concrete in accordance with the design. 

Completion and evaluation   

A CCTV survey was carried out to confirm that the works had been completed in accordance with the brief, after which asbuilt drawings were produced and warning tape installed above the new UTX location. Final site tidyup included backfilling the excavation, reinstating sleepers and repositioning the third rail, packing sleeper beds and cleaning the sleepers and rail. Warning plates were then also fitted to the sleepers. 

 

Outcome 

The project delivered a robust and fully compliant new UTX capable of managing track drainage effectively and helping to maintain a stable and well drained railway. Key outcomes included:
 

  • A safe, compliant and robust UTX installation designed to effectively manage track water in line with industry standards 
  • Enhanced operational reliability through improved trackside drainage performance 
  • Seamless integration with existing rail drainage infrastructure to ensure consistent system performance 
  • Long‑term resilience delivered through high‑quality installation, system integration and CCTV verification confirming that drainage assets are operating efficiently and in line with the project brief 

 


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