The railway infrastructure is composed of all those elements linked to the tracks, both main and service tracks and the train deviation branches, including the platforms and the electrification systems with all the elements that allow the electrical energy to reach the train, with the necessary power to achieve the necessary performance.
All railway infrastructure is divided into three main elements: the railway platform or substructure, the track superstructure and the railway installations.
The construction of railway platforms involves earthworks to build the embankments, trenches and tunnels needed to create an eminently rectilinear route with the strict slope requirements of the railways. In addition, in hilly areas, the construction of large structures such as bridges, viaducts, overpasses and underpasses will be necessary to overcome obstacles while maintaining the required platform characteristics.
Sando Construcción has participated in constructing railway platforms on practically all the high-speed lines in Spain and has extensive experience in this type of work.
Track electrification
The railway electrification system is the system that provides the electrical energy necessary for the trains to run on the tracks. It is one of the essential railway facilities on a railway platform.
Electrification systems are classified according to three primary parameters: electrical voltage, current type and train power supply system. The latter determines how the traction units of the trains are electrically powered. There are two main types, conductor rail and overhead contact line, called catenary.
Spain’s most commonly used railway electrification systems are 1 x 25 kV in alternating current and 2 x 25 kV in alternating current.
The railway electrification subsystem comprises the arrival of the high voltage lines of the supplying company at the traction substation to the power supply point to the train, which is the pantograph.
The main elements of railway electrification systems are the generators and transmission lines, the traction substations and the railway circuit.
The railway electrical system consumes or generates energy to supply electricity to trains. for this purpose A Power Electrical System (SEP) is defined to adapt the electrical energy, acquiring specific characteristics for the railway system. The railway SEP can be defined in two ways: interconnected to the country’s general SEP, which is the most common and is a system that consumes energy from the country’s electricity grid, or through its own railway SEP, which is a less commonly used system as there are normally electricity grids distributed throughout the country.
The transmission lines are responsible for sending and distributing the power produced in the power stations to the railway traction substations. In general, they carry high power in alternating current.
The traction substation is the facility responsible for connecting the railway electrification sections to the three-phase transmission grid. To do this, they transform voltages from grid levels, generally at 66 kV, to those of the railway catenary. Traction substations are classified according to the type of electrification of the track: AC traction substations and DC traction substations.
Railway electrical circuits consist of the overhead contact line or railway catenary and the accompanying and return feeder.
To ensure good electricity collection at high speeds, flexible catenaries are constructed in such a way that the geometry of the contact wire remains within certain limits, i.e. that it remains straight, parallel to the track and in tension.
At Sando, we are part of the complete process of construction and maintenance of railway infrastructures, platforms and electrification systems. We take care of the execution of the elements that make it possible for the energy to reach the train carriages through Sando Construcción and to maintain these infrastructures so that they continue to be produced efficiently over time through Conacon Sando.
