A milestone has been reached in the development of the Olympic Park site. The project to bury the Powerlines in the olympic park is one step closer as a breakthrough in one of the tunnels has been reached. The powerlines which currently overshadow the Olympic Park area in the Lower Lea Valley are to be placed in two tunnels underground. Organsers say the Tunnel Boring Machine - nicknamed 'Fionnuala' broke through into the deep shaft on schedule.