Some believe electrification has been a neglected subject in the UK for years. Now, as Network Rail rushes headlong into a major programme of new electrification projects, much has been written about contractors having to relearn old skills and develop new techniques.
However, it must be remembered that, in any electrification scheme, there is more than just a need for power supplies and complicated overhead wiring. Traditional civil engineering is needed as bridge clearances are improved, trackbeds are lowered, station platforms and canopies are trimmed and countless other preparatory works undertaken.
One of the first schemes to come to fruition is the North West Electrification Programme. Here, principal contractor J Murphy and Sons is using its expertise to tackle not only these electrification preparations but another of Network Rail’s initiatives, delivering a project through collaborative working.
Bridge clearances
Murphy is currently working with Network Rail to deliver the Phase Three structure clearance works of the Preston to Blackpool North (PBN) bridges scheme which will be delivered during Control Period 4 and into CP5 from 2014 onwards.
The first involvement by Murphy in the North West Electrification Programme was the reconstruction of three bridges on the Eccles section of the Liverpool to Manchester line. The company also completed Phase Two, from Newton-Le-Willows to Liverpool, and Huyton to Wigan. A total of eight bridge reconstructions within these two phases were successfully undertaken by the integrated project team.
As work progresses into Phase Three, Preston to Blackpool North, Murphy is applying its expertise and lessons learned to deliver each project with significant cost and efficiency savings.
The Preston to Blackpool phase of the £6.8 million structure clearance works project focuses on bridges located in Preston, Kirkham and Poulton-Le-Fylde along a 17 mile route. Murphy was awarded the design and build contract for the alteration and reconstruction of seven bridges of varying size and complexity to provide sufficient clearance for the installation of overhead line electrification (OLE).
The seven bridges in the scheme are in locations varying from residential areas to busy town centres. In addition, planning requirements determined that particular consideration be paid to the visual appearance of the completed structures.
Paul Mohan, Murphy’s contracts manager, explains: “The project team’s experience of the previously completed phases and the collaborative relationship we have established for these schemes in the North West have been invaluable in terms of benefitting from continuity. We have taken the lessons learned on earlier projects to apply to new, more complicated structures this time. Early Contractor Involvement (ECI) has been significant in that respect and critical to delivery as some of the bridges involved in the PBN package of works have required extensive modification.
“We understand the level of work involved and anticipate potential problems before they arise so that we have no surprises along the way. Innovation is achieved, not just in the use of new techniques, but also by the engineering- led approach and collaborative working to drive efficiencies, enabling the completion of work on time to high specification. It is these things that we can use to share best practice across our teams.”
Two elements of the project particularly demonstrate the success of this approach.
Two decks at Kirkham
Station Road overbridge in Kirkham was initially recommended for demolition and replacement. However, during the ECI process, it was identified that the bridge deck had recently been strengthened by the addition of an over-slab arrangement and the loadings were isolated from the original structure. As it was that original structure which was snagging the gauge profile of the proposed OLE, a design solution was identified to remove it whilst allowing the new deck to remain in place, an approach that created a safer working environment for the team.
Collaboration between Network Rail and designers confirmed the feasibility of removing the original deck from track level, reducing disruption. There were significant benefits that resulted as utilities did not require diverting and no road closures were required.
The utilisation of a ‘Megalift’ bridge jacking technique resulted in the old bridge being removed in three 29-hour possessions.
Service support at Tithebarn Street
Tithebarn Street bridge in Poulton was one of the bridges identified that did not have the required vertical clearance for the installation of OLE. It was therefore recommended that a deck replacement was the most appropriate solution to achieve the minimum 4640mm clearance.
The design included modifications to reflect build-ability and best practice from previous projects. With a high skew, the bridge carries a single carriageway road and is surrounded by multiple residential and commercial properties and access roads which severely constrain the existing highway alignment.
Prior to the diversion and access works, the team discovered multiple utilities that crossed beneath the bridge and could have potentially held up the project. In particular, fibre optic cables could not be diverted in timescales which suited the programme.
Working with Network Rail, the utility owners and local stakeholders, the existing work plans were adapted so that the cables could be supported in- situ which afforded considerable programme savings to the client. This close team work helped to identify and overcome all of the major issues, resulting in the bridge being reopened to traffic and pedestrians three weeks ahead of schedule.
The Murphy Third Party Coordinators developed close relationships throughout the lifecycle of the project with stakeholders affected by the works, including community groups, local residents and businesses. Information boards used on each of the different bridge projects provided key project information with dates of road closures and artist’s impressions of the site to better illustrate the works to the public.
The North West Electrification Programme is one of the many electrification projects underway in the UK, with the Great Western and Midland main lines and the Welsh valleys scheduled to begin shortly. Through the collaborative approach of Network Rail, Murphy and the supply chain, the team overcame the complex engineering challenges.
This approach was critical to the overall success of the programme and underpinned the team’s ability to deliver the project on time and to budget. It will surely be repeated elsewhere in the near future.
