[2] Construction began on 25 April 2012 and the link is expected to enter operational service in 2030,[3] delayed from the original estimate of 2026.

By the turn of the 21st century, a total of 70,000 goods and passenger trains were reportedly being run through the Semmering railway during each year, it is one of the busiest routes in Austria.

[9] Outside of railway infrastructure, a flood protection scheme is required to mitigate against the risk posed by the nearby River Schwarza while the relocation of the B27 [de] road would also be necessary.

[9][13] In June 2024, Porr and Rhomberg Sersa Rail Group were awarded a €176 million fit-out contract for the tunnel.

The central section is to consist of 26 crossover passages between the two tunnels, along with an emergency station; a pair of 420 metre-deep ventilation shafts are also to be dug.

[10][11] By 7 June 2016, work on the third section of the SBT had commenced; this meant that full-rate construction activity upon the project, which was reportedly costed at €3.3 billion as of this point in time, was now underway.

At Göstritz, a 1,000 metre access gallery and multiple 250 metre-deep shafts were constructed to facilitate conventional tunnel excavation methods.

[9] At Fröschnitzgraben, a pair of 420 metre-deep shafts, possessing a diameter of 22 metres, were dug ahead of the deployment of tunnel boring machines.

[18] Additional major works will include the construction of entrances in Gloggnitz and Mürzzuschlag, as well as ventilation shafts at Trattenbach and Sommerau.