Contractor Winvic is nearing completion of its £29m contract to build a new rail freight terminal for Prologis as part of DIRFT III – a 7.5 million sq ft extension to the Daventry International Rail Freight Terminal (DIRFT).
When completed, the new terminal will be capable of receiving up to 24 freight trains, each over 700m long, every day. Here, the containerised cargo will be off-loaded by reach stackers – special container-handling cranes – and stacked four high.
Highly specialised equipment, as well as specialist construction methods, are required for this element of the contract.
The terminal slab has to withstand not only the concentrated static loading of the stacked containers (each weighing up to 21 tonnes) but also the dynamic loads imposed by the reach stackers as they manoeuvre into position.
Around 30,000m3 of steel fibre-reinforced C50 concrete has been incorporated into the 79,000m2 terminal slab and Winvic has built 9km of new rail track to link the facility to the Northampton loop of the West Coast Main Line.
In mid-June Winvic began installation of a key component of the project, a bespoke rail traverser made by Sheffield-based rail depot equipment specialist Mechan.
The traverser will be used to move Class 66 locomotives sideways, after being decoupled from the wagons. The locomotives can then exit the rail head and travel back to the rear end of the 700m-long train ready to haul it out of the terminal once the containers have been off-loaded.
“It’s a dead end, so you have got to get the loco out somehow,” says Rob Smart, Winvic’s project manager on the scheme. “So the loco drives onto the traverser, decouples, and the traverser operator slides it sideways onto one of five parallel tracks.”
Traversers are familiar features of the rail network in continental Europe; less so here in the UK where road haulage dominates the logistics industry. Mechan’s engineering director, Martin Berry, says that traversers are more often used in the UK for handling rolling stock in maintenance depots, although Mechan has recently installed a large traverser to handle freight trains at the Port of Felixstowe.
At the DIRFT III terminal, a traverser is the simplest and most efficient solution, requiring about ten times less space than the alternative, a complex system of interconnected sidings.
According to Berry, UK demand for traversers has never been high, but is steadily increasing. “In the past 10 years we’ve sold eight traversers in the UK; before that, we’d only ever sold two,” he says.
The UK’s dependence on road haulage has reached the stage where rail freight is looking increasingly attractive. The motorway network is becoming more and more congested, observes Winvic director Rob Cooke – adding that the ‘smart motorway’ concept doesn’t appear to be improving matters.
“We can’t restructure the whole network,” he says, adding: “There are signs we will see more rail freight driven by private investment.” One of those signs is the government’s announcement of eight new ‘freeports’ to be established across the UK.
With DIRFT as a model, Winvic believes that similar rail terminals will be required as these new freeports develop. “Rail is more efficient and greener than lorries,” declares Cooke. Winvic is already eyeing up opportunities here.
The contractor is probably best known as a builder of industrial sheds and major distribution depots. But it is also one of only two or three leading contractors in the rail freight infrastructure sector, says Cooke.
Besides DIRFT, Winvic has completed several private-sector rail freight contracts recently, including the new Marks & Spencer distribution centre at Castle Donington, the SEGRO logistics park/East Midlands Gateway project and the Northampton Gateway rail freight interchange.
“It’s a niche – a specialist-market and at the moment we want to concentrate on our niche,” says Cooke. Nevertheless, Winvic remains active in other building and civil engineering sectors, including a significant presence in road construction, carrying out upgrade work for Highways England.
And there’s plenty of mainstream civils work involved in the DIRFT III project, too. Winvic started work on the site in June 2020 with a bulk earthworks programme comprising around 60,000m2 of cut-and-fill work and the placement of 40,000m2 of sub-base in preparation for construction of the huge terminal slab.
The project also includes the construction of three bridges. The largest of these is a 30m-span railway link carrying two rail tracks over the A5 trunk road, 2km north of junction 18 on the M1. This is a fully integral, single-span, prestressed concrete structure built on continuous-flight-auger piled foundations.
The span comprises eight precast concrete beams with permanent GRP formwork for an in-situ reinforced concrete deck.
The reinforced soil abutments and wing walls are faced with a composite system of interlocking prefabricated concrete units with soil tensile reinforcement and backfill.
Another bridge carries the rail tracks over the Clifton Brook watercourse. This is a 45m-long concrete arch bridge – essentially a tunnel under the made-up ground either side – built using the Matiére system, a segmental precast arch design. All the precast and prestressed components for the three bridges were supplied by Newark-based ABM Precast.
The third bridge diverts the existing bridleway up and over the new railway lines. This has a clear span of over 18m and a 5.5m-wide deck. Like the A5 bridge, this is an integral single span composite prestressed and reinforced concrete structure. The deck is composed of prestressed concrete beams with an in-situ reinforced concrete deck slab connected with abutments seated on spread foundations.
With all the major civils structures completed, installation of the rail traverser is the last big piece of the jigsaw to slot into place. Designed on a modular format the traverser is, at the time of writing, being delivered in sections and bolted together on-site. Installation and commissioning will be completed in July and the completed terminal infrastructure handed over later this summer.