Elizabeth and sister tunnelling machine Victoria were lowered 40m underground into a shaft at Limmo Peninsula, next to Canning Town station last month in preparation for the start of the eastern tunnel drive.
Victoria will also begin work on the eastern tunnels later this year.
Elizabeth has placed the first of 110,000 concrete segments that will line the eastern tunnels on the drive beneath the River Lea towards the new station box at Canary Wharf where work is already underway to prepare for the arrival of both machines next year.
Both tunnelling machines will then receive maintenance while in the large station box, before continuing their journeys towards Whitechapel, Liverpool Street and Farringdon. Elizabeth and Victoria are due to arrive at Farringdon in late 2014.
Andrew Wolstenholme, Crossrail’s chief executive said: “With the start of work on Crossrail’s eastern tunnels we are seeing the biggest construction project in Europe now tunnelling on both sides of the capital.
“By using boats and barges to deliver and remove materials from these tunnels, this will keep thousands of lorries off the road in east London.”