On Tuesday 26 May 2015 tunnel boring machine (TBM) 1 Elizabeth notched up two project milestones on the one day - breaking through at the future Showground station and reaching the halfway mark of her tunnelling journey. Elizabeth started her journey at Bella Vista in September last year and reached a historic milestone in January when she broke through into the future Norwest Station area. After undergoing maintenance she headed underground again in March and tunnelled toward Showground. Her breakthrough at Showground was a significant achievement - she has now tunnelled about 4.5 kilometres, the halfway point of the 9 kilometre distance to her final destination at Cherrybrook. Elizabeth will spend the next few weeks at Showground being prepared for the next stage of her underground odyssey the journey to Castle Hill.
Construction of the twin 15 kilometre tunnels is a team effort and when combined with Elizabeth's accomplishments, the four TBMs have excavated and built more than a third of the overall total of 30 kilometres. Collectively they are rapidly closing in on the project midpoint.