Twin mammoth caverns have been completed on Sydney’s Martin Place station six months before the schedule and after two years of excavation. In past 50 years, it is the first time that train tunnels are being built under the central business district.
The caverns which are located 28m below the street level – both 220m long and 14m wide – lie under Elizabeth and Castlereagh streets. Martin Place station is going to be an interchange which will link the South West line and Sydney Metro City– a 30km extension (Chatswood to Bankstown) and presently under construction – with the completed Stage 1 (North West metro from Chatswood to Rouse Hill. In addition, nine tunnels have been built to supply pedestrian access to commuters and to link with the current Sydney Trains network at Martin Place.
The excavation, which has been undertaken by two TBMs and roadheaders, has involved the removal of nearly 126,000t of sandstone. Recent months have seen a workforce of more than 600 people help complete the work. Now, the caverns are going to be fitted out with signaling systems, electronics and track work for the driverless metro trains. As it is expected to have the testing begin in 2023, the station is planned to open in 2024, and will see up to 200 trains rushing through at peak travel times.
Martin Place station shapes part of Stage 2 (South West and Sydney Metro City) which is being driven by five Herrenknecht TBMs. It is going to feature 15.5km-long twin-tube tunnels which will run under Sydney Harbor. Here, a mixshield TBM will bore in high water pressures 35m beneath the sea bed in clay, sediments and sandstone and be able to shift between slurry and EPB mode. The other four TBMs driving the routes south and north of the harbor are double-shield machines.
Australia’s biggest public transportation project and first metro line is Sydney Metro. Once it opens completely in 2024, it will have 31 stations and be 66km-long.