Lainz Tunnel

Accordingly, the section between Vienna and St. Pölten saw the construction of two new tracks on an alignment free from challenging gradients and suitable for high speed operations, which deviated far to the North of the original line.

[1][7] From the western end, the Lainz Tunnel turns southeast and passes under a stormwater retention basin and the forested area of Lainzer Tiergarten in Vienna's 13th district Hietzing.

It is 12.3 km long (15.4 including connecting ramps) and equipped with ETCS level 2 as well as the legacy PZB control system [8] During the late 1990s, geological surveys were conducted in preparation for the tunnel's construction; these determined that the intended route was feasible in multiple respects, including the local geology, geohydraulogy, and environmental impact.

Ahead of the primary excavation activity, numerous vertical wells were driven for the purpose of lowering the local water table.

The completed route has facilitated not only a considerable increase in freight capacity but a noticeable reduction in travel times as well.

[7] Since its completion, the Lainz Tunnel has formed a key civil engineering element for the east–west transit of railway traffic as part of the Magistrale for Europe.

The tunnel is also heavily used by freight trains bound for Vienna's central classification yard by way of a branch turning near the eastern end.