Electrifying Liverpool-Manchester

The Liverpool to Manchester Railway, constructed by George Stephenson and opened on the 15 September 1830, is credited with being the world’s first twin-track inter-city passenger railway on which all trains were timetabled and ticketed. Therefore it was only fitting that, in November 2010, the Government should announce that the Liverpool-Manchester route would be one of the first to be electrified as part of its new electrification programme.

A contract was awarded to Balfour Beatty Rail to undertake the electrification design and implementation works for Phase 1 of the route which connects Newton-le-Willows to Manchester – a distance of approximately 15 miles. The works also included not only the electrification but the signalling and telecommunications immunisation works required to bring the line up to modern standard required for a 25kV electrified railway.

In October 2012, Balfour Beatty Rail was also awarded a larger contract for Phase 2 of the route which adjoins and connects with Phase 1 at Newton-le-Willows and runs westbound to Edge Hill towards Liverpool Lime Street, incorporating the line from Huyton to Wigan. The Phase 2 works also include delivery of signalling and telecommunications as well as traction power supply elements.

The significance of this project was emphasised when Rt Hon Simon Burns MP, Minister of State for Transport, visited the Balfour Beatty Rail site facility at Tuebrook sidings in Liverpool on 15 November 2012.

Further phases of the project will be completed in conjunction with the Northern Hub project, providing connections to Blackpool and Preston.

Next generation equipment

The Liverpool-Manchester project introduces an innovative new generation of electrification equipment, developed by Network Rail, called the Series II Design Range. This allows for 25kV traction power at line speeds up to 100 mph and incorporates best practice from British and European railways, introducing technological innovations with a focus on whole life cost savings. It can be configured as a classic booster system or as an auto-transformer system, the configuration in which it will be used on the Liverpool-Manchester project. The contact wire is a solid 107mm² silver copper wire tensioned at 11kN, suspended from a 19/2.1 stranded bronze II catenary wire tensioned at 11kN by flexible current-carrying droppers. The nominal system height is 1300mm. An aerial earth connection will be mounted from the electrification structures as part of the earthing and bonding regime.

The contact and catenary wires in the new system are automatically tensioned using independent Tensorex C+ spring tensioning devices which use a spiral spring system. The Tensorex unit is compact and has a low visual impact. It is delivered ready to install, having undergone in-factory quality assurance, is easy to install and requires very little maintenance when compared to typical balance weight systems.

This modern generation of electrification equipment sees the introduction of the Omnia aluminium cantilever range in place of the more traditional galvanised steel tube arrangement. This lightweight ‘upside down’ cantilever has few components, comes preassembled in three standard sizes, and is easily installed and adjusted.

The Series II equipment has been designed for a 12kA short circuit fault level and all clamps and components sourced for this system are to be tested accordingly.

Liverpool-Manchester will also be the first electrification project to have fixed earthing devices (FEDs) installed, which have been introduced following Network Rail’s review of isolation practices across the network. FEDs are switches that can be operated to earth the overhead line equipment once the traction power has been disconnected and isolated. This allows the overhead line to be easily earthed for maintenance purposes from convenient locations along the route.

Chat Moss Challenge

One of the biggest challenges facing Stephenson, apart from unruly landowners and farmers opposed to the railway construction, was the infamous Chat Moss, described by the writer Samuel Smiles as “an immense bog of about twelve square miles, a mass of spongy vegetable pulp”. Stephenson armed his work force with planks strapped to their feet to stop them sinking into the Moss – the closest thing to PPE for the time.

Over its five mile stretch, the peat can reach up to six metres deep and was a formidable obstacle for Stephenson. After trying to backfill the area for several months to provide a stable base, preference was turned to ‘floating’ the railway across the area using heather bundles, brushwood mattresses and timber hurdles, each about 2.5 metres long and 1.2 metres wide, placed in layers to form a raft. This proved to be successful, and victory went to the famous engineer.

Stephenson’s technique, however, posed a significant challenge to today’s engineers as the timber layer installed by Stephenson was not to be damaged during construction. Careful survey work was carried out to position foundations away from the areas where the raft existed. This, however, resulted in foundations being placed anything up to eight metres from the running edge.

The Chat Moss stretch of the line required two different solutions for the electrification structure foundations: deep tubular steel piles of up to 14 metres in depth, and a mini-pile arrangement for areas where the presence of underlying rock made it impossible to drive the steel piles. There are approximately 120 mini-pile arrangements and 200 deep steel piles throughout the five mile stretch of railway across the moss, each with its own unique topographical and sub-strata issues, making this one of the railway’s most challenging geotechnical hurdles.

Deep steel piles, made from two halves connected together by high strength bolts, were first vibrated then hammered into position using rail-mounted plant. This was a very quick and economical solution and a number of piles could be installed during a single night-time possession.

The mini-pile solution was used when rock was identified from ground investigation boreholes or when the distance from running edge was beyond five metres (this being the maximum physical distance a deep steel pile could be installed using the on-track plant employed on this project). The mini-pile system consists of four or six concrete piles topped off with a concrete slab to which the steel mast is connected. The piles are generally anchored into the rock and provide a push/pull support arrangement for stability.

Innovative construction

Not only is the electrification equipment for the Liverpool-Manchester project innovative, but Balfour Beatty Rail also identified the need for a lean and efficient foundation installation process and developed a special concrete train for the project. This consists of two volumetric mixers mounted on a rail vehicle along with containers for the constituent parts of concrete; sand, cement, water and aggregate. After the foundation is excavated, the volumetric mixer can mix and deliver the exact amount of concrete necessary to form the foundation.

On completion, the mixer is switched off, effectively stopping the mixing process and ensuring that only the concrete required is made and installed. This is a very sustainable form of construction which reduces CO2 emissions from traditional road mixers, does not require mixing plants to be opened during the night and guarantees no waste concrete is made and left unused.

Logistics

In order to support procurement activities and to accurately and efficiently control materials on site, Balfour Beatty Rail’s own Material Control System (MCS) has been utilised on this project. The MCS software was developed in-house specifically for electrification projects and has proved to be an invaluable tool, ensuring that all necessary materials are supplied to the site on time. This system is currently being linked to a production management system which will enable the construction and design teams to share and manage live information, supporting lean and effective planning and efficient handback.

The first testing and commissioning work is scheduled to take place during a 54-hour possession over the Christmas period. This will see the line electrified through the Castlefield Viaduct junction area ready for a future tie into the Chat Moss lines when the permanent system is commissioned.

Phase 1 of the project is to be fully commissioned during September 2013. Following a period of driver training, the line will be ready in December 2013 to make history once again when the first electric trains run from Manchester Airport along the route to its connection with the West Coast Mainline.

The Phase 2 works are now at the detailed design stage, with commissioning of the scheme scheduled for August 2014 when, for the first time, electric trains will run on George Stephenson’s Liverpool to Manchester route.

  • MikeB

    The latest rumour is that the design of “Series 2″ overhead line equipment being installed in the North West could be incompatible with older EMUs such as Class 319s (destined for Northern Rail). It is said that the performance of the pantograph/overhead wire does not conform to modern tolerance requirements, laid down by European interoperability regulations. If this is correct the 319s will have to be completely re-engineered, which will delay their transfer from Thameslink even more. Perhaps the best option would be to order further Class 352s or Electrostars

    • Guest

      Hello Mike
      I beleive you have got it slightly wrong. Whilst the electrification system may not be TSI compliant, its pretty much the standard “BR” design that has been improved with better and more reliable components (also modern equivalent components where applicable), so infact there is a better likelihood of Class 319 operating as well as Electrostars. Hope this clarifies the misunderstanding.

      “Please note that these are my own views and not of my employer”

      • MikeB

        Thanks Guest. The rumour came from a certain rail enthusiast’s journal plus one or two other sources. Hopefully the Class 319s will indeed be compatible when (and if!!!!) they ever reach the North West, following the Thameslink delays.

  • Philip Miller

    The Victorian Railways Department , Victoria, Australia used spring tensioned overhead for iit’s 1500 v dc sub urban electrified network in the 1960s.

  • Chris Dugdale

    “the nominal system height is 1300mm” – sounds a bit as if designed for that other product from Liverpool – Hornby trains.

© Copyright - The Rail Engineer - Articles and Images by Rail Media are licensed under a Creative Commons Attribution-NoDerivs 3.0 Unported License.