Winner of The Heavies Job of the Year, the Collett Team were challenged with transporting a 4.72m diameter tunnel boring machine from Hackney Sub Station, London to Shawell, Leicestershire.
Having successfully dug part of National Grid's new London Power Tunnels route, TBM Cleopatra awaited transportation to Shawell where she would be stored.
Several site visits were undertaken surveying access through and from the Sub Station and Route Access Surveys and Swept Path Analysis reports were completed to determine the suitability of the proposed vehicle trailer combination, route and any potential conflicts along the way. Identifying various street furniture removal requirements throughout the route, the team also highlighted the narrow access from the Sub Station to the Hackney road network, in particular access via South Millfields Park, the residential Hillstowe Street and the following left turn to the A104. This wouldn’t pose an issue for the smaller loads, the 23 Tonne Tail Can and the 40 Tonne Cutting Head, but did prove problematic for the heavier loads, the 103 Tonne Forwarding Shell and the 105 Tonne Stationery Shell, which due to the size of the overall combination couldn’t facilitate the left turn.
To overcome this tricky aspect of the route, the Collett Team proposed a solution in which the heavier loads would make a right turn out of Hillstowe Street and the entire combination parked facing the direction of oncoming traffic. The ballast tractor would then be disconnected from the front of the trailer and re-attached on the opposite end, effectively flipping the combination 180 degrees without the need for physically turning the trailer and load, and allowing the team to then continue on the proposed route.
With access to the site limited to specific timescales the Collett Team arrived on Saturday 29th June to begin loading of the Cutting Head and Forwarding Shell, the first two components of the tunnel boring machine to depart for Shawell. The mobilisation of the trailer was transported to the location in modular pieces and built on site to avoid unnecessarily navigating the difficult layout of the Sub Station site twice. Once loaded the two trailers were left on site ready to depart the following morning.
6 members of the Metropolitan Police Department were waiting to escort the loads from Hillstowe Street at 5am, therefore the Collett Team were on site at the Sub Station and ready to depart at 3:30am. This ensured that there was ample time to navigate their exit from the Sub Station and journey through South Millfields Park. With the gates of the Sub Station having been removed and residents of Hillstowe Street informed to keep the street clear of cars the convoy began its journey.
Successfully navigating the narrow access from the Sub Station and through Hillstowe Street the two loads began their journey under the escort of four Police motorbikes, two Police cars and two Collett Escort Vehicles. The convoy continued on its journey through Hackney, and with all street furniture removals identified during the planning stages, smoothly navigated the busy London streets and successfully joined the M25 motorway for the onward journey to Shawell.
On arrival in Shawell the heavier load, the 103 Tonne Forwarding Shell, was delivered directly into the building with the Collett Team undertaking the Jacking & Skidding and lifting operations to successfully offload the component. The smaller load, the Cutting Head, was delivered to the rear of the building and unloaded by crane.
Two weeks later the other two components were collected following the same procedure and delivered without incident to Shawell.