With KiwiRail, Tonkin & Taylor and HEB Construction
Tunnel 21, also known as the ‘Tar Barrel’ extends 167m through a weak and fractured mudstone rock. Constructed during the ‘Golden Age’ of the railways (1870s-1945), the tunnel was the oldest tunnel between Christchurch and Picton.
Due to its age and restricted width, trains had to slow down markedly to travel through. While ongoing repairs and maintenance kept the tunnel operating safely, the decision was made by KiwiRail to close the tunnel and bypass it with a new route through a hill and beneath SH1, a little further south of the existing Tunnel 21. This upgrade increased the main north line speed, therefore reducing travel time and reducing operating costs.
HEB Construction were the main contractors on this KiwiRail project, and Moddex was privileged to work with the HEB Team to design, supply and install our proprietary Moddex barrier systems.
Why was Moddex selected?
The project was in construction over a 2-year period, so our handrails were supplied in stages to suit the construction program.
Moddex were a fast and cost-effective solution due to our modular flexibility. When materials arrived on site, there were no holdups and everything fitted in place without any additional labour to cut or weld required. This ensured a rapid install, as our product was delivered in stages to suit the construction program which meant there were no materials sitting around on site for weeks getting damaged.
A prompt delivery to ensure each stage of the project was on schedule was required, and Moddex delivered on time and within budget.
Producer Statement – Design
Another factor was the ability for Moddex to provide a producer statement (PS1) for each handrail design. This meant the design engineer of the project didn’t need to worry about this element, and could focus on other parts of the job.