Free Online HD on Lookmovie. One of six films which examine in depth the work involved in this great engineering project. As they are of a technical nature, they were only available for showing to suitable audiences. In preparation for the construction of the new Victoria / Walthamstow line two experimental lengths of tunnels are driven using different lining materials. The film shows in considerable detail the aligning of the cutting equipment, the operation of the shield and cutters and the two techniques of lining.