Abnormal Load Services (ALS) has transported a 4.72m-diameter Herrenknecht TBM from the manufacturer’s Schwanau headquarters to National Grid’s difficult-to-access construction site the in the Haringey area of north London, UK.

Costain will use the TBM on the first of two drives for the National Grid’s London Power Tunnels Project (see feature, page 76).

ALS delivered the TBM successfully to a tight deadline in five oversize ‘breakbulk’ components and 17 standard container loads. ALS arranged for the loads to be transported by road to a waterway where they were lifted onto a barge to be carried to the Zeebrugge ferry port.

Special arrangements had to be made at Zeebrugge by transferring the roll on roll off ferry to a special berth as the normal berth was not strong enough for the 183t trucks. Special beam/vessel carrier trailers transported the main shield and drive, and also the second can with erector, so that these large components could be carried safely under restricted bridge heights.

The final leg from Port of Tilbury to the Eade Road site required six police escort cars, three private escorts and a pilot car along major roads in the late evening to avoid traffic congestion. ALS surveyed the route for bridge weight and height restrictions and also arranged for a BE16 special order permit from the Highways Agency together with approvals from two police forces, four local authorities, Network Rail, London Underground, British Waterways and Transport for London.

The whole journey took six days for the main TBM components.