United Kingdom, Dec. 16 -- Balfour Beatty VINCI engineers working for the HS2 project claimed a UK-first over the weekend when they successfully slid an enormous 4,600-tonne viaduct across the M6 without closing the motorway - significantly reducing disruption to drivers.The 17 hour-long operation was the culmination of an epic three-stage process to assemble and install the 315-metre East deck of the M6 South viaduct, which will carry high-speed trains heading to Birmingham and further north.While the previous slide had required a weekend closure of the main carriageway, the team worked closely with National Highways to develop the 'fully restrained' process which allowed them to safely slide the final section above the moving traffic.It i...