KiwiRail required a new sub-station to be provided alongside an existing 1950’s building housing life-expired switch-gear. The sub-station transforms 11 kV power and converts to 1500V DC for traction supply for the Wellington Metro rail network.
KiwiRail power supply installations had previously been housed in concrete buildings constructed on-site with the electrical installation following. The Petone sub-station is the first KiwiRail sub-station constructed off-site and transported to site with all electrical equipment pre-commissioned. This approach means both the building and the electrical fit-out are undertaken in a factory environment, allowing improved quality control and significantly reducing the on-site time for contractors.
Octa provided Engineer to the Contract services for this FIDIC turn-key contract with ABB, and assisted KiwiRail in the study of all aspects of this new module’s requirements, including transport mobility, weathertightness, foundation requirements and temperature control and provided inspection audits at the factory during the construction and fit-out phases.
The building was completed under budget and was successfully commissioned with minimal defects. KiwiRail is planning for future sub-stations to follow this factory fabrication and fit-out philosophy.
The project incorporated several innovations which had not previously been used by KiwiRail including off-site sub-station building fabrication and electrical fit-out and transport to site. All exterior sub-station cladding was designed for a 50-year life with minimal maintenance. The sub-station also uses convective cooling for the Rectifier Room which was also a KiwiRail first.