Following completion of the two tunnels in April 2020, this exciting milestone marks a new stage for the project and is an important step towards completion of the Airport Line.
The rail starts out as 27.5m lengths of steel before being welded into giant 220m strings. Multiple teams work simultaneously to weld, transport and precisely lay the rail and sleepers to form the skeleton track in the tunnels, then pour the concrete that finishes the slab track.
Check out our tunnel fit-out and track laying fact sheet to learn more about what is currently happening underground.
Other sections of the tunnels have also seen plenty of activity recently, with several cross passages under construction at the same time and concrete pours for the tunnel invert slab now 80 per cent complete.
Above ground preparation is underway for the installation of the overhead line equipment, which will be powered by a 132kV/25kV substation located in High Wycombe.
New heights for Bayswater portal building
At the western end of site construction of the portal building has resumed, with steel structures already visible at ground level. Underneath the building sealing rings are being installed to both tunnel entries, ensuring the structures are waterproof.
At the eastern end the first few masts for the overhead line equipment have been erected, with more to be installed in the coming months. The masts outline the final location of the temporarily shifted Midland Line tracks, with city-bound trains to be rerouted across the dive structure.
The rail crew has taken residence at the shallow end of the dive structure, where welding of rail lengths will take place over the next couple of months.
Outside the dive structure, adjacent to Whatley Crescent, the remaining panels for the noise wall have been placed.
Steel works strong focus at Redcliffe
Steel structures for three of four above-ground rooms at Redcliffe Station have been installed, with the fourth not far behind. These rooms will accommodate staff areas and operational equipment, as well as a kiosk and public toilets. More steel, this time for the roof structure, has arrived on site and assembly is imminent.
The underground platform is nearing completion, with only the very last (of 12) topping slab left to be poured.
Sealing rings for the four tunnel openings (two at either end of the station) are also in progress at this site, as is waterproofing of a section of the ground slab.
Airport Central Station all about vertical transport
Lifts and escalator installation is still at the forefront at Airport Central Station. With seven escalators, including the longest single-span uninterrupted escalator in the southern hemisphere, and four lifts, the vertical transport crews are working hard.
At the very top of the building the station roof skylights have recently been installed, allowing for natural light to fill the atrium.
Glazing work is also ongoing at the elevated walkway – or main entry level – of the station.
At the same time staircase pressurisation fans and ducts are being installed to a number of emergency staircases at ground level.
Bus infrastructure topical at High Wycombe Station
With the eastern terminus station of the alignment well advanced, works now include the forecourt, where the bus bays will be located. Steel frames for the bus stop canopies have been placed, with roof panel installation underway.
Progress is also visible at the multi-deck car park site, with more than 100 building footing pits excavated and 79 foundations cast. More than 90 per cent of the storm water system has also been installed, and workers are preparing to erect the structure's first tilt-up panel, weighing in at more than 10 tonnes.
To (literally) round out the underground program, sealing ring works have also recommenced at the High Wycombe end of the two tunnels.
Countdown on for cross passage construction
Works at the three emergency egress shafts (EES) are predominantly taking place inside the ancillary buildings, where fit-out such as cable pulling and cable tray installation is undertaken by several MEP (mechanical, electrical, plumbing) crews.
Since last month's update installation of the remaining two of four steel modules for the stairs and lift shaft at Airport West EES has been completed.
The overall cross passage tally (structure complete) is now 12 of 15.