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Chalking up an early finish

Contract 330

Contract 330 East Thames, Medway Valley to Waterloo connection Alfred McAlpine/Amec JV Alfred McAlpine Construction/Amec Civil Engineering 16km Target cost £80M Key features: Civils work speeding to a wrap up on 18 December this year - the first CTRL main contract to finish. Big, largely chalk muckshift, especially for M2 and other road modifications. Rebuild of abandoned rail line involves total reconstruction but leaves environmental screens of overgrown embankment and cutting sides. Difficult at grade interface with existing railway at Fawkham Junction.

Alfred McAlpine/Amec Joint Venture is flying along on Contract 330 - the eastern end of CTRL section one.

Substantial lengths of sub-grade are already in place on the most advanced sections of the earthworks and all civil construction looks set to finish by the contractor's self-imposed target of 18 December this year.

It means that the railway-ready formation should be available if needed for system-wide track and power contractor Amec/Spie to run trials six months before its scheduled start. The only drawback is that all ballast and rails are to be fed in from the far end of the route at Beechbrook Farm near Ashford. Special arrangements would have to be made to bring materials from elsewhere to any major track installation work on C330.

But the real driver for finishing this year is simply that a contractor will always save money by finishing early.

McAlpine/ Amec's project director Bob Goldring saw an opportunity.

'It opened up possibilities for the trackwork but we had to discuss with the client whether he wanted it early, ' says Goldring.

C330 involves a substantial muckshift of 3M. m 3with hauls of up to 9km and Goldring was keen to keep control of the work and not to subcontract.

'That way we could peg the plant rates.'

As a result, AMPL plant logos are much in evidence throughout this predominantly rural section of the route. In-house companies Amec Piling, Amec Utilities and Buchan Precast Concrete were also engaged. But the three substantial steel bridges were put out to Fairfield Mabey, and Clubb Lafarge is 3of concrete needed from its plant.

Two thirds of the earthmoving has been completed since bulk excavation started in March last year. A mighty fleet of 63 articulated dumptrucks ranging from 25t machines up to hefty 40t Caterpillar D400s was at work until late November. Large amounts of chalk are still being moved, despite the season, but much of the dumptruck fleet is lined up by the site offices waiting for the weather to allow movement of the more moisture-sensitive material.

One of the most impressive cuts is not directly for the railway. Near the west bank of the Medway a massive depression has been created for the first stage of the remodelled M2 motorway junction 2 interchange. This junction will be finished later by M2 widening contractor Costain/Skanska/ Mowlem JV but a large part including rail over and underbridges was more logically constructed with the CTRL.

Another huge slot has been sunk into the chalk at the far, west, end of the contract where the Waterloo connection of CTRL is being built along the line of the abandoned Gravesend West Railway.

Superficially the concept of the new line following a route closed in the midBernard Boothroyd RLE contract manager on C330 Bernard Boothroyd is part of the huge team of people who worked on the Channel Tunnel and have come together again on the Rail Link.

Six years were spent on the tunnel with Halcrow. 'But I never got my picture in NCE, ' he says with feeling.

Then in 1994 Boothroyd was back at Halcrow's Vineyard House office in west London busy with a series of projects between short periods on site in Malaysia and Thailand. Four years ago he was seconded as part of Halcrow's team on CTRL, working from 106 Tottenham Court Road as package manager for Contracts 330 and 350.

On site with C330 he says: 'People took time to come to terms with the (contractual) system.' The approach to profit and risk helped a lot: 'There's a real incentive to have 'What if ' discussions.'

Paul Johnson RLE environmental manager 'The attention given to the environment on the CTRL sets new standards for the UK. Other projects will now be expected to meet them, ' says Paul Johnson.

He is responsible for a team of 50 specialists spread through the project working on design, consents and construction to ensure that the railway has the minimum possible impact on people and the natural environment.

Scope of this brief includes archaeology, ecology, landscape design, listed buildings, agriculture, air and water quality, and noise and vibration.

A director of Arup Environmental, Johnson specialised as an ecologist and environmental scientist then moved into environmental town planning. His first involvement with CTRL was during Arup's unilateral proposal to change the whole strategy of plans for the railway by crossing the Thames and bringing the line in through east London rather than from the south.

Four years ago he joined the project full time, and what was then London & Continental Engineering, with the brief to build up a team to deliver on the environmental obligations contained in the railway's Act of Parliament. 'The Parliamentary process gave the basis of the project, a reference design. That had to be taken and turned into a real engineering design, ' says Johnson.

'We have to deliver the client's brief to maintain high environmental standards.'

Creature comfort

On the CTRL, dormice, badgers, bats and birds have unprecedented priority for a construction project.

Environment is up with safety as priorities on site both for the contractor or client.

Anecdotes abound throughout the length of the trace. It appears that the environment specialists employed by RLE do not have to bully contractors into line.

On Contract 330, one of McAlpine/Amec JV's drivers discovered that after he had left his dumptruck parked up off hire, a pied wagtail had chosen to make its nest under the throttle pedal.

The machine stood idle for a further three weeks until the birds had flown but the dumper was charged to the contract as if it had been working all the time.

'It eats into the cost, ' says project director Bob Goldring. 'But it's illegal to destroy nesting birds.'

1960s might seem to involve heavy maintenance and refurbishment to bring the wayleave up to standard.

On the ground it is not quite like that.

One side of the original cuttings, and embankments, of this 3km dogleg to Fawkham Junction has been left as an overgrown, environmental screen. The other - and virtually every original structure - has been ripped out as if they had never existed. Eurostars negotiating the tight 106km/h turn into this old route will be running along an entirely new railway formation, even though they can only get up to 120km/h before taking the sharp curve at the far end.

Despite the rural character of the contract there has been a lot of utilities diversion work. 'It looks like a greenfield site but there are intense levels of utilities, ' says RLE contract manager Bernard Boothroyd.

Goldring agrees. He cites the example of the tightly programmed cut and cover tunnel at Halfpence Lane near the centre of the contract. 'The construction sequence is easy to analyse in detail but you must not take your eye off the ball on other things, ' he warns.

'Diversion of stats can become critical.'

Archaeological relics are not confined to the surface deposits on C330.

The contract involves a considerable amount of excavation near to upper levels of chalk. Senior geotechnical engineer Akis Andreou of Halcrow has found the need to keep a close lookout for dene holes in these strata.

Dene holes are the remains of old shallow chalk mines. Before the 19th century, farmers employed labourers to quarry chalk for spreading on the fields to counter acidity in the soil. Shafts were dug 5m or so down to just below the top of the chalk with adits driven out in all directions. The shafts were later backfilled but the tunnels were not.

The old tunnels are exposed or collapse when earthmoving machinery strips the upper strata and runs over the chalk. Careful backfilling and compaction is needed to ensure that they do not interfere with the integrity of the railway formation to be built above. The compaction specification beneath the railway is more demanding than for a road. Where chalk fill is being used it is compacted with grid rollers, generally at a moisture content of 20% to 24%.

Subgrade being laid on the top is recovered railway ballast, screened and blended by Foster Yeoman at the Isle of Grain.

Bob Goldring Project director, Alfred McAlpine/Amec Joint Venture C330 Bob Goldring and much of his team moved straight across to Contract 330 from the A417/A419 private finance road project near Gloucester, which they finished 30 weeks ahead of programme.

'All contractors bidding for work on the CTRL were a bit wary at first. We were concerned about whether partnering would work on a target cost project. But once it started off you wonder why you didn't do it always.'

The finish of C330 has been pulled forward from midsummer 2001 to a target date barely 26 months after the contract was awarded. 'We started excavation in March (1999) and aimed early on to hit it very hard.'

Helen Glass RLE senior archaeologist 'Years ago archaeologists would tend to excavate, say, a Roman villa and ignore the context.

We've tried to look at the wider area things are set in.'

Glass has a team of four at RLE who set the specification for investigations and supervise the work done by specialist contractors.

With Section One archaeological investigations almost complete she is concentrating on how to collate the overall findings: 'Kent has always been a transport corridor and it would have been a rich area for archaeology wherever the Rail Link route went.'

She says 'We have a unique opportunity to present material.'

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