It’s not often that we have the pleasure of reporting on the new construction of a main line railway in England. But, in the heart of the country, a 4km stretch of brand new double track electrified railway is taking shape. Not heard of it? Well, to many of us it does almost seem like a well-kept secret, but look left as you travel the West Coast main line (WCML) between Stafford and Crewe and the activities can be glimpsed.
The brief view of earthworks seen from a speeding train belies the true extent of what’s involved. Technically this is an upgrade, but with eleven new bridges, 10km of 100mph track, major river and road diversions and three new junctions – this is, by any standards, a substantial project. So what’s it all about?
The work forms part of a £250 million scheme known as the Stafford Area Improvements Programme (SAIP). It is designed to remove the last major bottleneck on the WCML, at Norton Bridge. The full programme comprises three key stages:
Upgrading of the slow lines between Crewe and Norton Bridge;
Resignalling of Stafford station and the installation of a down goods loop;
Separation of the slow lines at Norton Bridge onto an entirely new alignment and the creation of a grade separated junction.
Alliance
All of these works are being delivered by an alliance that involves four partners participating in one collaborative contract. It follows the Australian ‘Pure Alliance’ model in that the member companies are working together as one organisation. Known as the Staffordshire Alliance, it is a partnership of Atkins, Laing O’Rourke, Network Rail and VolkerRail.
This is the first example of such an alliance operating within the UK rail industry and it has been driven by the need to embrace the findings and recommendations of the McNulty report. In other words, to reduce costs and improve the quality of what’s being delivered. Network Rail says it wants to ‘develop mature collaborative relationships with key industry participants, creating a fundamentally different operating landscape.’
Different it is. The alliance draws upon the specialist skills and experience offered by the participating organisations, but with complete integration and equal sharing of the benefits and risks. Decisions are made on a ‘best for project’ basis. Whilst the collaboration must not remove accountability to deliver, it addresses concerns that quality and scope may be sacrificed in order to achieve cost savings when delivering multi-disciplinary programmes.
The result is a joint project team with widespread trust and the elimination of man marking. It looks beyond purely financial interests and creates incentives for the partners to work together in areas such as quality, safety and environmental impact. On SAIP, the alliance has also been important in developing a robust strategy for possessions on the WCML and to facilitate working with adjacent line open.
Slow lines fast
The works to upgrade the slow lines over an 18-mile distance between Crewe and Norton Bridge were completed in March 2014. Extensive OLE modifications were carried out by Network Rail’s overhead condition renewals team while track alignment works were undertaken by Network Rail/Amey Colas. In addition, four new banner repeater signals were installed.
The line speed has been raised from 75mph to 100mph, allowing the slow lines to be optimised for London Midland and CrossCountry services. This also gives improved access to the fast lines for maintenance work.
New signalling
SAIP Phase 2 involves the soon-to-be-completed re-signalling of Stafford station, with scheme boundaries at Shugborough on the London line and Penkridge on the route to Wolverhampton. Running concurrently with it is the upgrade of the slow lines between Stafford and Great Bridgeford to allow 100mph running.
Signalling in the Stafford area had seen little investment since the 1960s and was deemed life expired. There have also been capacity constraints through Stafford station itself. The signalling system is therefore being replaced entirely. All platforms at Stafford will become bi-directionally signalled and the line speed on the Up fast is to be increased. Additionally, a new 775-metre Down goods loop was installed to the south of the station during the May 2015 bank holiday weekend.
The new signalling includes 78 new signal heads, 176 axle counters and five WESTLOCK interlockings and is to be controlled from a desk at the Rugby Route Operating Centre (ROC). In fact, this will be the first desk at the ROC to become operational. The scheme is to be commissioned over the August bank holiday weekend. Following this the two remaining electro-mechanical signal boxes, Stafford No.4 and Stafford No. 5, both dating from the 1950s, will be demolished.
Congested
Norton Bridge Junction is the point at which the twin-track line to Stoke and Manchester Piccadilly diverges from the four-track route that serves Crewe, Liverpool and Scotland. A mixture of InterCity, commuter and freight trains all have to share a complex flat junction. Services for Manchester that need to traverse the junction, especially those using the slow lines, can create congestion and pathing difficulties.
It is estimated that there are currently 40% more passenger journeys and 60% more freight than 20 years ago and passenger numbers are forecast to double within the next 20 years. With capacity on the route at an all time high, intervention was needed to ease the bottleneck at Norton Bridge and to future proof it for decades to come.
The ambitious solution has been to separate the slow lines at a new junction near Little Bridgeford. They will now follow an entirely new alignment, which includes a flyover that passes over the WCML almost at right angles. Seen as a project of national significance, the Norton Bridge project has been the subject of a Development Consent Order application which was approved by the Secretary of State for Transport in March of this year. This follows a consultation process dating back to 2010. Work on site was commenced during the spring of 2014.
Phase 3 – Grand Junction
The WCML route through Norton Bridge was an early railway, being constructed in the 1830s by the Grand Junction Railway. It passes immediately to the east of the Norton Bridge hamlet, following a series of sweeping curves. There are several roads and rivers in the area and the constructors chose a course for their railway that took advantage of the land contours and minimised bridge construction.
Creation of a flyover has meant that the slow lines need to take a path through open countryside. Several routes were considered and the Staffordshire Alliance worked closely with the local community during the design process. It was clear from the outset that roadways and watercourses would have to be diverted. Environmental issues included protected woodland and, of course, the ubiquitous Great Crested Newts.
The chosen alignment had to be something of a compromise, but a key factor in its favour is that the cut and fill is in balance, obviating the need to haul material over the local highways. A route further west would have created excess spoil, whereas a route further east would have required large quantities of imported material. The chosen route therefore has the best carbon footprint.
Split
The concept is that the Up and Down slow lines will leave the existing WCML route at Little Bridgeford Junction following an almost straight route, climbing to the north at a constant gradient of 1 in 125. Making use of the height gain, the twin-track route swings to the north east after Searchlight Lane to pass above the WCML well to the north of the existing Norton Bridge Junction. The new lines then fall to tie in with the Stoke line at a new junction near Yarnfield.
The existing four-track route through Norton Bridge will be reduced to three tracks by the removal of the Down slow. The new Down slow will split at Searchlight Lane with a new single track heading north to join end-on with the existing Down slow near Heamies Farm.
The existing junction at Norton Bridge will be reduced to a bi-directional single line chord. This line is retained only for flexibility and will not normally be used by timetabled services.
Bridges
The scale of the civil engineering works needed to achieve all this is truly enormous. There are ten new bridges and the enhancement (new deck) of one existing bridge, four river diversions, the diversion of three roadways (1.2km of new road) and two footpaths. Major diversions to utilities have included the re-routing of three high-pressure gas pipelines and a pipeline carrying aviation fuel.
Upon leaving the WCML route at Little Bridgeford, underbridge No.1 carries the slow lines over the River Sow. This is followed closely by underbridge No.2 which takes the railway over a tributary called Meece Brook.
The route then enters a cutting that is 85 metres wide and up to 15 metres deep, graded with a 2 in 1 batter. Approximately 650,000m3 of material, largely composed of Mercia mudstone, has been excavated from the cutting and has been transported via internal haul roads to create embankments and bunds elsewhere within the scheme.
Overbridge No.3 crosses the embankment at its mid-point and carries the diverted Searchlight Lane. The next significant structure is the intersection bridge No.5 that straddles the WCML.
Just to the north, the diverted B5026 crosses the WCML on overbridge No.5A. The new line is then on a five metre high embankment as it crosses the flood plain of Meece Brook. Stabilisation of the ground here has been achieved by rock piling. Over 2000 stone columns have been driven-in in this area.
The embankment is intersected by the diverted Meece Brook at underbridge No.6. Its abutments accommodate a second deck (bridge 6A) that carries the continuing diversion of the B5026. At this point the roadway is higher than the railway and it passes over bridge 6A on a three metre high embankment.
Overbridge No.7 takes the new railway under a minor road, closely followed by underbridge No.8 as Yarnfield Junction is approached. The latter involves the widening of an existing bridge by replacement of the deck. Overbridge No.9 carries a footpath, replacing Mid Norton footpath crossing.
On the single track formation north of Searchlight Lane Junction, overbridge No.10 carries the B5026 and underbridge No.11 as at a further encounter with the meandering Meece Brook.
Pre-cast
Most of the bridge components have been manufactured at the Laing O’Rourke pre-cast plant in Worksop and at a pre-cast yard within the main project compound near Chebsey. These structural components were then transported to site by road, saving on-site construction time. Entire abutment shells, for instance, were craned into position onto pre-installed pile mats. Bridge 6 has two such stacked abutment shells to support the rail deck and three for the road deck. The pre-cast method has also reduced the need for skilled labour at the worksites and a reduced need for personnel to work at height.
The completion of overbridge No.5A in May 2015 was a milestone event in the project. The internal haul road was extended over it, allowing the transportation of excavated material to form the embankments east of the WCML. Articulated dump trucks have carried 4,000m3 of material per day across this bridge – a load every 45 seconds across the bridge, necessitating traffic light control.
Of the 650,000m3 excavated from the cutting, approximately 230,000m3 has been used to build embankments and the remainder has been used for landscaping bunds. The bunds have a maximum slope of 1 in 8 and will be returned to agricultural use upon completion of the project. At the time of writing, the completion of all eleven bridges was expected by the end of August and the earthworks are planned to be finished by November 2015.
Railhead
Track laying was commenced from the new junction at Little Bridgeford in May 2015 and has followed the advancement of the cutting. This temporary railhead allowed delivery of materials for drainage, capping and track to be delivered from Bescot yard in 1200 tonne train loads, with up to five trains per week using the siding. It is estimated that this has saved 200 lorry journeys into and out of the site every week.
Track construction trains are scheduled to visit the site again on 26 September, 7 November and 12 December 2015. The signalling works are due to be commissioned at the end of March 2016.
Community and environment
An intensive programme of public engagement has taken place, including presentations, leaflet drops and consultation events. The alliance has also engaged with local schools and a legacy steering group has been formed to look at ways in which the project can make a lasting contribution to the surrounding community.
Unavoidably, the cutting north of Little Bridgeford has needed to pass through a small part of Yeld’s Rough. This is an area that includes protected woodland and ponds providing a habitat for species including badgers, otters, barn owls, bats and great crested newts (GCN). Flora and fauna was translocated from the affected area. As part of this process a total of 14km of GCN fencing was constructed.
Archaeological studies have taken place as the excavation work has progressed. Significant finds from the early medieval period have been uncovered, including the wooden lid of a butter churn. It dates from 715-890 AD when the area was at the heart of the Mercian kingdom. Evidence of prehistoric activity had been uncovered in the same area.
Benefits
The requirements of SAIP are to create the capability to deliver more services, facilitating a recast of the timetable by the winter of 2017.
Two additional fast trains per hour (off-peak, each direction) between London Euston and the North West – these paths are to be created by moving the twice-hourly Birmingham/Liverpool services to the slow lines.
» One extra fast train per hour (each direction) between Manchester and Birmingham – pathed for a Class 350.
» One extra freight train path per hour (each direction) through Stafford.
The ‘Pure Alliance’ contractual arrangement has worked extremely well in the delivery of this complex multi-disciplinary programme.
It’s estimated that it has so far created cost savings within SAIP of 10%, with further savings forecast.
The alliance is also helping to deliver the programme one year early, by December 2016. Clearly, the Pure Alliance structure has generated a highly motivated and engaged team that has encouraged innovation, safety and the use of best practices throughout. This surely represents a model that can be used again, and it’s not hard to imagine where.
More than one bottleneck may well have been eased by this radical new approach.