Giant spider-like machines help complete Tycannah crossing loop works
During a couple of days in April strange looking, spider-like robots joined construction crews to finalise a crucial section of the Narrabri to North Star Phase 1 alignment.
May 29, 2023
Close up of a motorised handling gantry at work lifting a turnout. Photos courtesy of Peter Borrelli.
How do you make light work of a mammoth task? Bring in reinforcements of course! While undertaking work to finalise the Tycannah crossing loop installation in April, Inland Rail contractor Trans4mRail employed insect-like machines to move two preassembled turnouts into place to connect a new crossing loop track and siding to the upgraded mainline.
Crossing loops along the Inland Rail alignment consist of a 2221 metre section of track that runs parallel to the mainline with two connection points, or turnouts at either end. The turnouts allow a train to roll off one track onto another.
The motorised handling gantries (MHGs), used for the first time on the Inland Rail project, are also known as telescopic switch handling machines or, colloquially in Australia, turnout jacks. They enable jobs that typically take days to complete, to be done quickly and safely in just a few hours within tight track shut down / closure periods. Seven MHGs, worked in unison to lift and move 80-plus metre sections of track from beside the mainline into their final positions.
The MHG’s are controlled on site by remote control and use telescopic arms to lift an otherwise cumbersome structure. It then moves it horizontally before placing it down about a half a metre closer to the new location. The machine repositions itself and begins the process again. These precise and coordinated steps are repeated until the turnout is perfectly in line with the two pieces of track it will connect.
Aerial view of the northern turnout nearing its final position to connect the mainline to a crossing loop. The turnout’s original location is visible by the tracks the sleepers left on the ground to the left of the structure.
Before the MHGs got to work, crews cut and removed the sections of track that the turnouts would replace. Once the turnouts were installed, the new sections were ballasted, tamped, welded and destressed. Finally, specialist signalling subcontractors installed and tested the points motors and associated equipment that drives the turnouts.
Worker saw cutting a section of the mainline to create a gap for the destressing process to occur. Crews worked around the clock for the first three of the seven days of the job to meet the deadline.
Night time tamping of the turnouts to allow installation of the turnout motors and signalling works to commence the next day.
The works occurred partly in conjunction with an existing Hunter Valley network shutdown between 3 and 10 April, and after consultation with local grain customers to minimise impacts. During this time passengers on the regional XPT Explorer service between Moree and Narrabri were bussed around this section.
Prior to the shutdown the Tapscott Road level crossing was also closed and all traffic diverted via Burrington Road to allow signalling at this level crossing to upgraded.
Narrabri to North Start Phase 1 Project Director Peter Borrelli was pleased with how well everything came together.
“The job including all signalling, testing and commissioning was completed 15 hours ahead of schedule without any safety or environmental incidents and any community complaints. Without the help of the MHGs, work would have taken much longer, causing more disruption to the network.”
Close up of a newly installed turnout with the control motors in the foreground.
Significant preplanning was undertaken for the shutdown, requiring a coordinated effort across several teams.
“The Inland Rail Narrabri to North Star Phase 1 project team (design, delivery and signalling RCP systems teams), ARTC Operations, Interstate, Hunter Valley Network and Customer Service divisions and our contractor Trans4m Rail including specialist signalling subcontractors Aldridge Signal Infrastructure and Green Aspect Consulting came together to make the closure a success” Mr Borrelli said.
The Tycannah crossing loop is one of five along the Narrabri to North Start Phase 1 alignment and will allow trains travelling in opposite directions to safely pass each other.
Aerial view of a newly installed turnout. The end of the preassembled piece of track that was connected to existing track can be seen at the top of the image.
