In Melbourne’s southeastern suburb of Narre Warren, traffic congestion at the Webb Street rail level crossing had long been a thorn in the side of daily commuters. With over 13,000 vehicles passing through the intersection daily and boom gates down for up to 33% of the morning peak, frustration was palpable among drivers. The Victorian Government recognized the pressing need for a solution and launched the Webb Street Level Crossing Removal Project to untangle this daily traffic knot and enhance safety for all road users.
To address this, a one-kilometer section of the rail line needed to be elevated, with the crown jewel of the project being two massive steel half-through bridges, each weighing an incredible 680 tonnes. However, building these enormous structures using traditional stick-built methods would have caused widespread disruption, requiring significant road closures on Cranbourne Road—a crucial arterial route in the area.
Enter Mammoet, a global expert in heavy lifting and transport. Tasked by McConnell Dowell, the project’s principal contractor, Mammoet was entrusted with delivering a solution that wouldn’t paralyze the suburb’s traffic flow. The Accelerated Bridge Construction (ABC) method.
ABC isn’t your run-of-the-mill construction technique; it’s an innovative approach where large structures are fabricated offsite and then transported to their final destination. This method allowed Mammoet to sidestep the need for prolonged road closures, a huge win for local commuters and businesses. By constructing the bridge sections near the installation site, they were able to transport and install the massive steel structures in just a matter of days, minimizing disruptions to the community.
The execution was nothing short of impressive. Mammoet employed Self-Propelled Modular Transporters (SPMTs) in combination with the JS500 jacking system to lift, transport, and place the bridge sections. First, the SPMTs raised the bridge from a height of 1.5 meters to 4.2 meters, preparing it for the main lift. The bridge was then jacked up to a towering 9 meters—clearing obstacles like street furniture and power lines—to begin its journey through Narre Warren’s crowded streets.
The transportation process wasn’t a simple drive down the block. Navigating a 50-meter-long, 680-tonne structure through congested urban streets required meticulous planning and precision, akin to threading a needle in a haystack. Mammoet’s team skillfully maneuvered around houses, trees, and power lines to ensure the bridge sections reached their destination without a hitch. Once on-site, the massive steel pieces were carefully jacked down into place, resting firmly on their foundations.
By using the ABC method, Mammoet managed to avoid significant traffic delays and safety risks commonly associated with traditional bridge construction. The result was a swift, efficient installation that kept the lifeblood of Narre Warren’s road network flowing.
The completion of this project stands as a testament to the power of innovation in the field of construction and logistics. With cars, pedestrians, and cyclists now passing seamlessly under the newly elevated rail bridge, the Webb Street Level Crossing Removal Project is a shining example of how collaboration, engineering expertise, and modern technology can transform urban infrastructure for the better. This level crossing was the 14th removed on Melbourne’s Pakenham Line, marking another milestone in the Victorian Government’s efforts to make the rail line boom gate-free by 2025.