High-speed Line HSL Zuid

The HSL-Zuid is a high-speed railway line between Antwerp and Amsterdam. At the Belgian border, the HSL-Zuid railway line connects to the HSL 4 line. Infraspeed was in charge of the construction of this railway line. Infraspeed asked Deerns to install the HVAC and fire alarm systems. Deerns was involved with this project from the initiation phase to realisation.

Tunnels and viaducts

The HSL Zuid route includes a number of tunnels, viaducts and deep cuttings at which engineering structures have been erected to house communications and security equipment. Specific requirements were drawn up regarding the climate in these installation rooms. The HVAC system in these buildings ensures that the required interior climate is maintained. The buildings are also fitted with fire alarm systems.

Systems engineering

Systems engineering was applied in the development of the installations. This is a method in which a series of technical processes is analysed, defined, integrated, implemented and designed in order to ensure that all system requirements are met. Interfaces with other installations, connectivity and risks are identified and dealt with in full, resulting in a complete, integrated and holistic total design.

The HSL Zuid project not only involved the realisation of the railway line but also a 25-year operating contract. With regard to the systems, it was therefore crucial that not only the investment costs but also the operational costs (maintenance and energy costs) formed part of the design. The HSL Zuid railway line must be available at least 99% of the time. It was for this reason that RAMS analyses were carried out for the various systems, including HVAC and fire alarms. Under RAMS (Reliability, Availability, Maintainability & Safety) the systems are analysed according to the EN 50126 international standard. This extensive and precise analysis makes it possible to determine the best concept within a dynamic process.


The Heating, Ventilation and Air Conditioning systems are housed in the tunnel constructions and at the cuttings. These systems ensure that the required spatial conditions in the installation rooms housing the communications and security equipment are maintained in order to maximise its operational life. The HVAC system is controlled, operated, guarded and monitored by the control system. The control system has been engineered in such a way that the various systems can be monitored centrally by Infraspeed Maintenance and fault analyses can be conducted, allowing efficient maintenance and fault handling to be carried out.

Fire Alarm

The tunnels and tunnel constructions are fitted with fire alarm and evacuation systems. Deerns carried out the performance assurance, certification, delivery and validation of the fire alarm system, the evacuation system, the stationary train detection system, the control systems between installations, and the smoke detection and gas extinguisher systems.

The Deerns quality system seamlessly integrated with Infraspeed's quality control department which was headed by Siemens staff members. This method of working creates a traceable design which forms the basis of rapid response times during the operating phase.