Kiwirail Hillside Workshops redevelopment

Project requirements

Challenges: 

The design of the new KiwiRail Hillside mechanical workshop aimed to enable mechanics to work efficiently on up to 21 locomotives, wagons, or carriages simultaneously. A key feature of this design was the incorporation of service pits to provide access to the undercarriage of the vehicles. These pits would also have lighting and would be used by mechanics with specialist tools so they required special attention to ensure that no water would ingress. 

The workshop was to be built on the site of the demolished structure, requiring careful management of soil contaminants. Although inland, the site is prone to tidal influences and is low-lying, which increases the risk of flooding. The main challenges were to develop a robust waterproofing solution for the service pits that could withstand site contaminants and fluctuating water table levels. 

Allco Solution

To address these site-specific challenges, the Volclay range was chosen for the waterproofing of the service pits. 

Volclay Voltex DS was applied to waterproof the base and slab transitions. Voltex DS combines the proven waterproofing capabilities of Voltex with a high-strength HDPE liner, offering excellent chemical resistance and minimal water vapour and gas permeability. This made it the perfect choice for handling the demanding on-site conditions. 

Volclay Swelltite was used to waterproof the pre-cast panel sides of the service pit. Swelltite is a reliable and effective solution, whether a structure faces continuous or intermittent hydrostatic pressure. By bonding an active bentonite layer between tough, puncture-resistant geomembrane layers, Swelltite provides both passive and active barriers, greatly reducing the risk of leaks. This is especially beneficial in dealing with fluctuating water table conditions, adding an extra layer of protection. 

The combination of Volclay Voltex DS and Swelltite membranes, alongside the use of Waterstop RX, ensured a seamless installation and a comprehensive, long-lasting solution to prevent water ingress. 

Execution and Results: 

The successful installation was made possible through the collaboration of Approved Applicators Titus, Main Contractors Calder Stewart, and the Allco Technical Advisory Team. Through excellent communication and multiple on-site meetings, the project was executed smoothly. 

“During the process we had multiple consultations with Allco but in particular with Adrian who I found immensely helpful, there's definitely no substitute for experience in these sorts of situations. The outcome was fantastic for us and the client Calder Stewart and Kiwi Rail. The construction company Calder Stewart running the site were very happy to be able to liaise with myself and Allco directly to achieve a mighty result” Murray Morgan, Titus Waterproofing 

Conclusion: 

Allco is proud to have contributed to the revitalization of the KiwiRail Hillside Workshops, helping to preserve its place in New Zealand’s rail history while ensuring a modern, durable facility that can serve the needs of KiwiRail for years to come.