> Which would require the digging of a third hole where the TBM "drill heads" meet. In most projects it's called a station. http://www.crossrail.co.uk/constru

> Which would require the digging of a third hole where the TBM "drill heads" meet. In most projects it's called a station. http://www.crossrail.co.uk/construction/tunnelling/meet-our-giant-tunnelling-machines/ http://www.crossrail.co.uk/construction/tunnelling/meet-our-... Occasionally you'll have dive sites that are not at/near stations, but not that often. https://www.sydneymetro.info/station/blues-point-temporary-retrieval-site https://www.sydneymetro.info/station/blues-point-temporary-r... https://www.sydneymetro.info/tunnelling https://www.sydneymetro.info/tunnelling