Tracks, Bridges, Tunnels
Tracks
Alingment Design
VRT, High-Speed Lines (HSL) in the Czech Republic are being designed for speeds of up to 350 km/h, although only 320 km/h is expected. This is reflected in laying down a route that includes bends with a minimum radius of 7 km. The HSL will be used for passenger transport, with a few exceptions, so the route can be designed with significantly higher gradients than normal, up to 35 per mil.
Planning a route for HSL means it should avoid built-up areas, natural landmarks, etc., and at the same time it should trace the landscape to the highest extent possible (moderate cuttings and embankments). In local conditions in the Czech Republic, this can be a difficult task.
Design of the Railway Superstructure and Substructure
The High-Speed Lines resemble modernised current Czech key railway corridors. Visible differences between the High-Speed and conventional lines include the difference in the width of the space alongside the line and the fencing. At first glance, the superstructure is the same as on the double-track electrified line. The rails are fixed on concrete sleepers, which are laid in a gravel bed on an asphalt concrete layer.
Railway Stations on HSL
These stations will beare going to transport nods, where it will be possible to change from High-Speed Train to other forms of transport: car, bus, regional train or bicycle.
You can find out much more about the upcoming terminals here.
Bridges
Bridge Structures on HSL
High-Speed Lines in the Czech Republic are designed for speeds of up to 350 km/h, a fact that must be reflected in the design of bridge structures. Respect for Czech and European standards, especially the Eurocodes, is a matter of course.
Typification of Bridge Structures
In order to streamline preparation, especially for frequently recurring types of bridges, we aim to standardise bridge designs. The use of standardised structures not only accelerates the design stage but also saves time during implementation. Another important benefit is financial savings, where, for example, the prefabricated manufacture of dozens of identical culverts is cheaper than their individual design and production.
Emphasis on Sustainability
Bridges are designed for a minimum service life of 100 years and should ensure easy maintenance of the structures as well as easy access to the individual bridge components. The growing trend of integral and semi-integral bridges on High-Speed Lines in Europe is also on the road to sustainability. For example, they use fewer bearings, which are structural components with lower service life.
Safety Parameters
Safety is an absolute priority when designing High-Speed Lines. Of course, there will be guardrail, traffic barrier systems and other measures to prevent vehicles from falling on to the track. Overhead contact line protection will be installed on the bridges and footbridges. Fencing will limit the entry of unauthorised persons to the track area.
Source: SNCF
Landscape Permeability
Bridging HSL for all types of roads, watercourses and floodplains is essential for good landscape permeability. Similarly, bridges will be built in the migration corridors of small and large animals. The aim is to preserve all existing transverse connections to the highest extent possible.
Tunnels
The Importance of Tunnels
Tunnels are usually built where the terrain cannot be crossed otherwise. They are usually among the most expensive construction projects. Except for the tunnels in the Central Bohemian Uplands and Ore Mountains, only shorter tunnels will be built. More information about the tunnel through the Ore Mountains can be found here.
Placing the Tunnel Portal in the Surrounding Environment
The tunnel portals will be set in deference to the surrounding landscape. Trains passing through the tunnel at high speed create a pressure wave (shock wave effect), which can be accompanied by a loud sound on the opposite side of the tunnel. Although the dull sound is heard only briefly, a solution must be chosen so that no one is bothered. One of the possible measures to reduce this sound wave are vents on the tunnel portals, so that the air pushed by the train spreads out into the surroundings and does not cause noise.
Safety in Tunnels
The basic requirements for the safety design of tunnels are based on European Union Technical Specifications for Interoperability (TSI), which also include a specific section on Safety in Railway Tunnels (SRT).
The railway tunnel itself is an area with minimal risk of fire due to the small amount of combustible materials present. Given the length of railway tunnels today, and the fact that operating rules do not allow trainsets to stop in the tunnel, a fire can theoretically occur only in the event of a failure of the train itself as it passes through the tunnel or stops. However, we are prepared for such situations. Trains are dimensioned so that even in such an event, they are able to reach a safe place that is equipped to assist passengers and to enable emergency services operations.
Geological Surveys in Tunnel Design and Construction
At the preparation and design stage, engineering geological surveys provide a source of information on the geological background. Their task is also to identify potential pitfalls and highlight problems that may arise during construction. In the case of tunnels, the geological survey will provide important information on the nature of the rocks present and the geotechnical and structural properties of the rock mass. This will enable us to more accurately determine the difficulty of the tunnel construction, including the requirements for the boring machine.
The importance of the surveys is also financial: the more information available, the easier it is to avoid costly changes to the technical design of the project later.
Impact on Groundwater Resources
A common public concern with tunnel construction is the negative impact on groundwater resources. Therefore, a hydrogeological survey in and around the future railway corridor is carried out before the start of construction works. Its purpose is to describe and evaluate in detail the hydrogeological conditions at the site, highlight the water resource protection zones and map existing wells, boreholes and resources that could be affected by the construction.
Regular monitoring of water sources is carried out before, during and after the construction works to assess the impact of the construction on water quality and quantity. Both surface water and groundwater are monitored.