Channel Tunnel Rail Link (CTRL) construction seen between the London international railway stations of Stratford and St. Pancras (at King's Cross). A supply train carrying wall sections is travelling through one of the two tunnels. The twin tunnels of this rail link stretch 7.5km under London to form Britain's first high-speed railway that will carry Eurostar Channel Tunnel trains into and out of London. Photographed in early 2004.