The 900 tonne tunnel boring machine (TBM) is on her way to Cherrybrook, 9 kilometres away, as part of her job in delivering Australia's biggest public transport project. Elizabeth is one of the four mega machines which will deliver Australia's longest railway tunnels—15 kilometre twin tunnels from Bella Vista to Epping. Tunnelling started on the $8.3 billion North West Rail Link four months earlier than expected and, in further news for the project, the next two tunnel boring machines will also be in the ground before the end of this year. Elizabeth was assembled over seven weeks by 71 workers at the Bella Vista tunnelling site. It took two 500 tonne cranes about 7 hours to get just the circular cutter head in place. Each of the 40 cutters on the cutter head weigh 250 kilogram and are replaced every three weeks because of the forces of tunnelling.
Designed specifically for Sydney's geology, Elizabeth will cut through 120 metres of Sydney sandstone and shale a week, on average. She is her own self contained work station operating 24-7 with a rotating crew of 15 workers and is connected to power, ventilation cooling towers, water pump, a water treatment plant and a massive conveyor belt.