About the Stepani T3 tunnel
It is the shortest tunnel on the second track, 335 metres long, and the first tunnel from the direction of Divača, under the Kraško rim. Together with the Osp Tunnel (T5-6), it is classified as a short tunnel, which, due to its length, does not require forced ventilation and escape routes, which in medium and long tunnels are provided by lateral tunnel exit pipes or by cross-pieces in a parallel service pipe. There are no occupied structures on the surface of this tunnel in the tunnel construction impact area.
Length of the tunnel
Work on project
Excavation work
Tunnelling is construction work involving the excavation and removal of material necessary for the construction of a tunnel.
It is carried out in two phases: first the upper part of the tunnel (the calotte) is excavated, followed by the lower part of the tunnel (the step with the floor arch).
Progress of excavation works
Inner lining system
The completed internal lining gives the tunnel a distinctive shape, as it gives the underground space a uniform appearance and a smooth surface.
The construction of the inner lining system consists of: the floor vault, the foundations of the inner arch, the waterproofing of the tunnel, the longitudinal lateral drains and the inner arch, which is concreted with a movable tunnel formwork.
Interior lining progress
Other concrete works
In pre-construction, the term "other concreting works" usually covers all concreting activities that are not directly related to the main tunnel structures, such as primary and secondary arches. These works include: the execution of the fill concrete under the corridor, the kineta wall and the fill concrete above the floor vault.
Such works often also include adjustments to the concrete structures for the installation of technical systems and are essential to complete the tunnel in accordance with the technical and safety requirements
Progress of other concrete works
Tracks
A track on a rigid base:
Rigid track is a modern form of track that is used successfully all over the world, requires less maintenance compared to conventional shaft track, has a longer life expectancy and provides a more comfortable ride. The use of a rigid track system eliminates the possibility of track geometry errors during maintenance work. The possibility of direct attachment to structures, the lower structural height and weight compared to conventional track, make it the most optimal solution for tunnels and bridges. The expected service life of a track built on a rigid base is 50 to 60 years.
Track laying progress
Vehicle network
The tunnel catenary is a key component of the electrification of a railway line, enabling trains to be powered by electricity. After the track has been laid, the construction of the overhead contact line typically includes the following steps and elements: installation of the supporting structure, installation of electrical cables and wires, insulation and protection, and tensioning systems.
In tunnels, limited space and specific conditions (e.g. ventilation, humidity, vibration) require the use of specially adapted materials and construction solutions to ensure the durability and reliability of the overhead contact line.
Progress of the overhead contact line in the main pipe