Challenges on the project included underpinning a heritage building and a high rise commercial tower, working in close proximity to the public and transport routes with diverse neighbouring stakeholders, complex service relocations and within strict environmental controls. In response, the project team developed several innovations:
* Complex underground services relocation presented challenges including the re-design of a major    
 tunnel section to accommodate a major Sydney optic fibre cable duct.
* The team maximised the internal height of the tunnel (in an area of extremely low clearance to buried services) by developing a tunnel lining solution which replaced the traditional approach, comprising of a primary and secondary lining, with a sandwich waterproofing layer.
* A kink in the tunnel was required to enable the tunnel to continue at the off-shoot. The “kink” was required to take a double vault load. The primary linking of the the kink was a marvel of tunnelling primary support, involving heavy section steel sets combined with reinforced concrete and  pre-tensioning.. The resulting structure was only possible due to multiple layers of innovative processes used in a combination never before used in tunnel construction in Australia.
* A stationary knuckle boom crane was installed inside the extremely tight tunnelling worksite to service tunnel logistics. This replaced the need to use a mobile crane in the roadway, reducing the time required to work in the roadway (and disrupt traffic).
* Use of complex precast panels to expedite deliver.
* The innovative solution to underpin the existing 11-storey heritage building in York Street to allow for tunnel construction proved significant in limiting any defections outside allowable tolerances.
*Community – The team contended with a complex web of major Sydney services at the intersection of Kent and Napoleon Streets. Several months of night work was carried out to relocate major sewer, electrical and gas services on major Sydney roads directly adjacent to serviced apartments and a hotel. The project team involved the community in developing solutions to reduce construction impacts.