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Crossrail On the Right Track with JCB
Costing around $25 billion, the new underground rail line across London is the largest civil engineering project currently in Europe and presents huge engineering and construction challenges. The project involves constructing 42 km of new rail tunnels under the City linking existing Network Rail services from Maidenhead and Heathrow in the west and Shenfield and Abbey Wood in the east. New underground stations at Paddington, Bond Street, Tottenham Court Road, Liverpool Street, Whitechapel and Farringdon are also being constructed. Sitting right at the heart of the London network, Farringdon Station between Charterhouse Square and Smithfield Market is fundamental to the project. When complete, more than 140 trains per hour will flow through the Farringdon interchange and because it is the only station from which passengers can access all three networks – Thameslink, Crossrail and London Underground services – it is set to become one of Britain’s busiest train stations. The station is split into two worksites – the Eastern Ticket Hall (ETH) and the Western Ticket Hall (WTH) – both surrounded by residential and commercial properties and typically congested London streets. The long-reach JCB JS220 is working at the Eastern Ticket Hall removing spoil. Groundworks have already been completed by Laing O’Rourke/STRABAG joint venture and construction work is now being carried out by GFK – a joint venture between BAM Nuttall, Ferrovial Agroman and Kier Construction. Excavation in the City of London brings its own particular challenges. At Farringdon digging down to 35 m for the new ETH will be needed to complete the station construction. Initial excavations have revealed skeletons of 13 adults under Charterhouse Square which archaeologists believe are victims of the Black Death which struck London around 1350. The ETH site is also adjacent to Smithfield Market, the largest and oldest wholesale meat market in the UK dating back almost one thousand years. The foundations of the current Grade II building – built in 1868 – are very close to a new escalator barrel which goes down to the new platforms and therefore requires extensive underpinning and jacking to ensure there is no movement or settlement of the structure. After consultation with Lynch Plant Hire – one of the main equipment rental companies working with the major contractors and equipment supplier for the Farringdon Station site – it was decided to use a JCB JS220 long reach excavator which when fitted with an 8.7 m boom and 6.4 m dipper has a maximum dig depth of 12 m and a maximum reach of 15.6 m. The better the reach, the more ramp material can be removed, reducing the work of a smaller excavator operating at the lower level. While long reach excavators are generally designed for waterways maintenance applications and fitted with ditching or weed mowing attachments, the JS220 is an effective muck-shifter when fitted with a general purpose 0.5 m3 bucket and seen on many applications such as ports, sand pits and city centers requiring the long reach capability. Weighing 23.7 t, the very stable JS220 is one of the mid-range excavators in JCB’s long reach line-up which extends from the 13 m reach JS145 to the 21.1 m reach JS360 LC. Operating the machine is Lynch operative Kim Bash. “Because of the depth of the spoil below the level of the tracks the JS220 long reach was the obvious choice,” he says. “The machine is powerful and quick which makes it ideal for loading trucks. Currently we are doing about 30-35 loads a day which is disposed of in Dartford. The excavator could easily cope with almost double that but traffic and the number of available wagons reduces this number.” “The machine was used to build an earth ramp to allow the large piling rigs to track down to the lower level. It also worked at the lower level clearing around the old tunnels, building a work platform for the piling rigs and clearing up when finished,” he adds. “Now that this has been completed it was tracked back up to street level and is now working at removing the ramp. Because of the length of the ramp and the fact that the JCB can only work from one position at the top of the ramp, a smaller 13.5 t zero tail-swing excavator is helping push the spoil closer so that I can reach it and load the trucks. When completed the smaller excavator – which is light enough – will be lifted from the lower level by a crane,” concludes Mr. Bash. Power for the JS 220 is supplied by an Isuzu 4HK1X Tier 3 emissions compliant engine producing 172 hp. JCB has, however just launched a brand new JS220 model at Bauma 2013, which is the first JCB excavator above 20 t operating weight to adopt the company’s highly-efficient Ecomax diesel engine. It will result in Tier 4i compliance, a 10% cut in fuel consumption and improved engine responsiveness without the need for a diesel particulate filter (DPF). All equipment on the Crossrail contract has to comply with strict engine emissions noise regulations and dust pollution, which on the JS220 meant the retrofitting of a DPF. The machine is also fitted with a simple red/green light cab mounted emissions monitor, which alerts the driver should emissions be too high. The latest JCB JS 11 to 15 t excavators all feature Stage IIIB/Tier 4 Interim Ecomax engines and are the only crawler excavators in this weight category that meet the current emission standards without the need for a DPF or an exhaust after-treatment additive. “Everyone on site is very pleased to see the distinctive yellow of a JCB excavator arrive on site. JCB has a very good image and the performance and reliability are excellent. This JS220 has an aftermarket fitted DPF and monitor, however the latest excavators with the new Ecomax engines would be able to operate on site without any costly added emissions controls. The current engine is very fuel efficient and this makes a huge difference in the fuel costs of the machine for the client,” said Rob Lynch director of L. Lynch Plant Hire and Haulage Ltd. |
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