The Newly Opened Diabolo Tunnel Below Brussels Airport Features State-of-the-Art Safety System
By Marcel Hassenewer
On June 8, 2012, the Diabolo tunnel officially opened in Brussels, Belgium.
This 12-km (7.5-mile) tunnel is situated 100 ft beneath the Brussels Airport. The infrastructure project took five years to complete, at a cost of approximately $900 million.
The Diabolo tunnel stands out thanks to its comprehensive safety system. In case of a fire or similar emergency, corresponding emergency response is triggered. In such an event, Phoenix Contact PLCs control all safety systems beneath the airport.
Faster, Safer Service
Travelers can cover the distance between Antwerp and Brussels Airport in only 34 minutes using the Diabolo tunnel. The journeys from Mechelen and Leuven take 10 and 14 minutes, respectively, with no transfers. Diabolo is also connected to the European high-speed train network, so travelers can reduce travel times and shorten the commute between Amsterdam, Paris and Frankfurt to and from Brussels Airport. An entirely new infrastructure was built for this purpose, including a section of track on the wide median of the E19 highway, numerous bridges and many kilometers of tunnels under the airport’s take-off and landing strips.
Belgium has experienced a series of rail accidents over the past few years, so railway safety was a very important part of the tunnel build. For this reason, all new rail tracks for the Diabolo project were equipped with electronic beacons or transponders, known as ETCS Eurobalises, one of the components in the new European Train Control System. The Eurobalises prevent trains from passing stop signals. Due to the stricter requirements of the Belgian infrastructure administrator Infrabel, the tunnels under Brussels Airport are now the safest in the entire country and have become a model for similar domestic and international projects.
Adaptable Components and Systems
Fabricom GDF Suez won the contract for the safety technology for the tunnel and underground train station. Mario Brusselmans, senior rail project manager at Fabricom, stated, “We were able to secure the contract in no small measure thanks to our close partnership with Phoenix Contact. As part of our joint bid, the automation specialist adapted its components and systems to the client’s requirements, while other companies merely drew upon the existing products.”
A new concept for marking escape routes was developed. The dynamic evacuation guidance (DEG) system consists of aluminum parts fastened to the wall of the tunnel. LED profiles are inserted in these sections of the tunnel at intervals of 33 cm (13 in.), creating a dynamic lighting system that indicates the escape route. If a fire or other emergency requires passengers to leave the train and exit the tunnel on foot, these lights illuminate the escape route.
IP67-rated DEG modules are usually 4 m (13.1 ft) long and interconnected via redundant LED controllers. The LED module controllers are located in small cylinders. All LED controllers are linked to each other via a complex redundant cabling concept that supplies power and transfers data, saving space, time and money.
Redundant Evacuation Concept
LED controllers are based on Phoenix Contact Inline controllers installed at intervals of about 100 m (330 ft) in so-called modular service points (MSP) cabinets. The Diabolo tunnels contain about 100 MSP cabinets. Every ILC 1xx Inline microcontroller controls the LED controllers installed on both sides of the cabinet. This usually concerns only the next 100 m of LEDs in one direction. However, if a fire cuts off an adjacent ILC, the LEDs in the other direction can also be controlled. In other words, the DEG system is configured redundantly.
An industry switch from the Factoryline product range connects the ILC with the central controller, while a DC UPS power supply unit supplies power to the components installed in the cabinet and the DEG modules. I/O modules ensure communication with subordinate sensors.
Certain MSP cabinets contain two of each component. This is due to the fact that, in single-track sections, the LED profiles fitted on both sides of the tunnel are controlled by one cabinet, which is why an additional ILC was installed for the LEDs on the other side of the tunnel. In that case, a fire-resistant RF1U cable, laid under the tracks, links the ILC and LED controllers. The remaining cables do not have to be fire-resistant, because in the event of a fire, the closest MSP cabinet can take over, something that helps lower costs.
Four Phoenix Contact RFC 470S safety controllers are deployed for decision-making concerning the DEG module controller. The safety controllers are mounted in a central control cabinet. All ILCs and the RFC are connected to each other at this point via a gigabit ring structure. There are two identical safety controllers. The first one is installed underground, and the second aboveground and outside the tunnel for redundancy. If an RFC 470S fails due to a fire or other incident, the second safety controller takes over its function within milliseconds.
The most important of the four safety controllers is the FS-RFC (fire scenario). It triggers the emergency response and evaluates the type of emergency. The decision of the FS-RFC is based on input signals, so that it only takes action if a fire has in fact started or if the train is moving at less than 5 kph. Fires are detected by the Fibrolaser and/or measuring points. The Fibrolaser is a glass-fiber cable installed on the tunnel ceiling that detects temperature fluctuations with an accuracy of 0.1° C and a resolution of 3 m. Fire detectors or emergency buttons are used as measuring points at different locations, such as in the train station and the engineering rooms.
Sensors are mounted about 20 m (65 ft) apart on the tracks for measuring the speed of trains. They determine the stopping or passing of the measuring point at a certain time. The sensors are linked with the ILCs in the assigned MSP cabinet, as well as alternatively with the controllers of the previous or next cabinet. This ensures that signals are still received from every second sensor if an MSP cabinet fails due to fire. The sensor signals are now transmitted to the TL-RFC (train location) in the central control cabinet via the ring network. The location and speed of the train are calculated there.
Automated Safety Systems
The TL-RFC continuously transmits its data to the FS-RFC. Based on that information, the FS-RFC can determine which components and systems are in service or out of service in the tunnels and the accompanying structures/buildings. This includes the DEG system that indicates the escape routes. Commands are transmitted to the ILCs that control the LEDs via the DEG-RFC, the gigabit switch and the Ethernet connection. In addition to the DEG system, the FS-RFC is responsible for the following additional safety systems:
- Starting the emergency power generator
- Switching on of fans as well as the smoke and heat-extraction system
- Opening and closing of barriers
- Activation of fire water pumps
- Automatic switching on of lighting throughout the entire structure/building
- Loudspeaker announcements in the train station and on the platforms instructing passengers to remain calm and exit in an orderly manner
- Automatic opening of emergency exits
- Closing of fire rolling gates to shut off passageways
- Activation of smoke screens in the train station and on stairways
- Automatically stopping of elevators on a safe floor
- Halting of escalators
- Disabling of access control.
Automatic alarms for the airport, designed to ensure that no other passengers enter the train station, and the BMS (Building Management System) are also triggered. The BMS control room transmits the report wirelessly to the control room in Antwerp and, shortly thereafter, to Leuven and Mechelen, so that no further trains pass through Zaventem.
Fabricom GDF Suez has also chosen Phoenix Contact components, systems and solutions for other projects. Mario Brusselmans stated, “We are also working with Phoenix Contact in other Diabolo subprojects that we have been awarded, one such example being the contract to install electromechanical systems in the structure. The two companies have now been partners for several years, because of the user-oriented approach taken by Phoenix Contact and due to the speed and flexibility with which they are able to implement the requirements.”
This article was written by Marcel Hassenewert is with the Industry Management Infrastructure/Industry Solutions group, Phoenix Contact Electronics GmbH, Bad Pyrmont, Germany, with editing by Haroon Rashid, Industry Manager, Transportation Infrastructure, Phoenix Contact USA, Middletown, Pa.