Brussels is modernising and extending its metro network

Posted: 3 May 2016 | Luc Bioul and Luc Derie, STIB | No comments yet

370 million journeys are undertaken each year in the Belgian capital and year on year increasing use is being made of the buses, trams and metros belonging to the Brussels Public Transport Company (STIB). In order to keep up with the ever increasing number of travellers – and continue to provide them with high-quality, efficient public transport – STIB is working on large-scale sites, three of which are directly related to the backbone of its network: the metro. In an interview with Intelligent Transport, Luc Bioul and Luc Derie of STIB illustrate how the creation of a new line, the conversion of a section of pre-metro into metro, and the modernisation of its signalling is set to change the face of Brussels’ public transport over the coming years…

Brussels is modernising and extending its metro network

Today this Brussels company’s network totals four metro lines, 17 tram lines, 50 bus routes and 11 night-time bus routes, serving 69 metro and pre-metro stations and over 2,000 stops. STIB serves the 19 municipalities of the Brussels-Capital Region and 11 suburban municipalities, comprising a total surface area of 241.5km2 . Each day more than one million trips are made and this number increases each year. The metro, with its four lines, forms the backbone of the Brussels transport network, where numerous bus routes and tram lines converge.

From the 1960s until today

The Brussels metro was constructed and opened in the 1970s, but its origins were in the 1960s, with something special and unique to Brussels: the pre-metro. Before commencing the large-scale works necessary for constructing a metro network (a long and relatively onerous project), it was first decided to build tunnels and stations to match the size and demands of a metro system. They would be operated by trams, gradually and section by section, until the arrival of the metro. This more rapidly implementable compromise gave rise to the pre-metro in Brussels. These infrastructures were then progressively adapted, in phases, to accommodate the metro.

The pre-metro and the Brussels metro have undergone numerous changes since their launch in the 1960s and 1970s: extension of the pre-metro network, extension of the metro network, as well as the creation of entire new lines. The construction sites will make their mark on the landscape of the Belgian capital and the lives of those who live and work there.

Today the continual increase in use, and the development of new districts and new industrial zones, makes it necessary to strengthen the STIB network. As a result, the bus network is about to be completely redesigned and new tram lines will be created and extended. The large-scale construction sites anticipated by Brussels and the STIB teams will affect the very heart of the network with the modernisation of the metro’s safety signalling, the conversion of a section of pre-metro into metro, and the drilling of an extension of the metro line to the north of the city.

21st century signalling for a 21st century metro

In order to cope with the increased recorded use of the STIB network – mostly by metro users – it is necessary to increase capacity. It is not possible to accommodate this influx of passengers with the existing number of metro trains. Increasing the frequency of trains (currently 2 minutes 30 seconds on Lines 1-5, and 3 minutes on Lines 2-6 at peak hours), in order to end up with a 2-minute or, in time, a 90-second interval – will make it possible to absorb this influx of passengers. However, this will require the modernisation of all of the existing safety signalling in the metro.

“KCV, the technology currently used for metro signals, safety and rolling stock, dates from the 1970s, explains Luc Derie, Manager of the Metro Modernisation Programme at STIB. “At that time, this was the very first computer-controlled signalling system and things have changed a lot since then.”

The first-generation equipment has served its time and it is becoming difficult to find the parts necessary for repairs. Furthermore, to develop the network, more recent technologies should be used, but that would create a network which is “non-homogenous and therefore much more difficult to operate,” emphasises Luc Derie. Present-day signalling also requires more maintenance.

Therefore, in order to continue to ensure the safety of its metro network and increase the frequency of its trains, STIB must switch to a new type of signalling system – CBTC signalling (Communications-Based Train Control signalling). “With the CBTC system the train continuously communicates its position via Wi-Fi, as do the other trains,” explains Luc Derie. He continues: “The system compares the two pieces of information and, on the basis of, amongst others, the speed, position and safety distance to be respected from the first train, indicates to the second train the speed at which it may travel. Thus the speed of each train is dynamically managed while at the same time maintaining sufficient safety distance and optimising the route travel time. The train can therefore drive without human intervention.” Thus, they are on their way to an automated metro.

The CBTC signalling system will be brought into operation on the STIB network in phases. During implementation of the first phase on the East-West line (of both Lines 1 and 5), the driver will always be responsible for obtaining authorisation to leave the station, and for opening and closing the doors, but the speed and the stopping of trains will be managed by the CBTC system. In the second phase, the trains will travel without a driver at all. All manoeuvers (acceleration, deceleration, stops, departures, and the opening and closing of doors) will be performed without any human intervention.

“It is normal to work in phases, because it takes time to implement a new system, a new manner of driving trains,” Says Luc Derie. The new CBTC system will first be installed on metro Lines 1-5, using antennae (parts of the network outside the shared section), in phases. Once the system has been installed on an antenna, all checks will be performed. The other antennae follow, and finally the twin-line shared section. Therefore, from the start both systems (KCV and CBTC) will be present on the antennae with the CBTC in ‘shadow’ mode, in order to test the performance of communication between a train and the track-based equipment. In order to start testing and operating the CBTC system, there must be a minimum fleet of trains equipped with the CBTC system. The new trains to be ordered must also be able to operate using the KCV system as, during the transfer phase, part of the line will be operated using CBTC and the other part will remain in KCV while any bugs are eliminated from the CBTC system and until sufficient trains are equipped with CBTC for the entire line to operate using CBTC. The installation of the platform edge doors (which are indispensable for the automatic operation of a metro network, as they ensure the safety of passengers entering the train and prevent intrusions onto the tracks and suicide attempts), will commence as soon as the CBTC system is operative everywhere. STIB will begin by installing these platform edge doors in three stations before moving on to the rest of the network.

“For several years STIB has been working on the development of this new system, which has already proved successful elsewhere. The system has been adapted to meet the needs of our dense network, with its special topography featuring numerous bends and slopes. CBTC signalling should be operative on Lines 1-5 by 2020,” specifies Luc Derie.

A new metro line across the whole of Brussels, from north to south

Each year Brussels gains more and more inhabitants; new districts spring up; industrial zones develop, and transportation requirements increase daily. Over the coming years to better serve the Region – especially the municipalities and districts located to the north and south of the city – the STIB network will be undergoing major and essential change, creating a whole new metro line by extending infrastructure towards the North of the Region and converting part of the pre-metro into a metro set-up. This project represents a total investment of €1.6 billion.

“For the third time in its history (1976, 1988 and now over the coming years), STIB will be converting a line currently operating as a pre-metro for use as a metro,” explains Luc Bioul, Senior Vice-President of Operations at STIB. From the start this section, including tunnels and stations currently used by underground trams, was designed and scaled for future use as a metro. In any case, changing from one mode to the other requires some adjustments, such as raising platforms, the addition of a third rail, modification of the electricity sub-stations, etc. It will also be necessary to replace a station initially built for trams with a new station, in order to create a new connection between existing tunnels and to create and convert a current station into a real transfer station.

The 4km extension, including seven new stations in densely populated areas, will present many technical challenges for the teams of STIB, Bruxelles-Mobilité (the administration of the Brussels-Capital Region responsible for infrastructure) and Beliris (a collaboration between the Federal State and the Brussels-Capital Region).

“To drill this tunnel we will adopt a different technique to that used in the creation of the metro; and we have opted for a technique never before used in Brussels: that of the tunnel boring machine,” states Luc Bioul. At that time, the method used was actually known as the ‘Brussels’ method: two vertical walls are constructed in the ground, an upper plate is installed, traffic is able to resume on the surface, while the tunnel is drilled inside this compartmentalised space. Even though this technique is still successfully used today (amongst others, to create future stations), new techniques have been created and it is this so-called tunnel boring machine technique (as used to drill the Channel Tunnel) that shall be used to drill the metro extension towards the north of Brussels. The tunnel boring machine will start work at the future terminus of the line, at the site of the future STIB metro depot, and will carry on into the ground, drilling, evacuating and installing concrete sections, in order to obtain the final size of the tunnel right from the start.

The so-called ‘ground-freezing’ technique will be used to dig and construct the seven new stations along the route. The ground of the tunnel, on the site of the future station, will be frozen. Workers will then dig out the frozen ground to create station platforms, and the station will be connected to the surface using the so-called ‘Brussels’ technique.

“STIB, Bruxelles-Mobilité and Beliris have conducted socio-economic studies in order to determine and optimise the future route of this northern metro extension, and the implementation of future stations, in order to optimise service in the areas it traverses. Before long, we will be able to offer all STIB clients a brand new transport service,” states Luc Bioul.

Coming soon: the new face of public transport in Brussels

With all of the project design and development, impact assessments, planning permission, consultation with public authorities and drawing-up of specifications, etc. that is involved; developing public transport infrastructure in urban areas is time consuming. Work is due to commence in around 2018, and by 2025 STIB hopes to be able to present the capital of Europe with a new underground public transport system, for the benefit of all.


Luc Bioul is a trained civil engineer who joined STIB in 1981 and has been a member of the Management Committee since 1995. Having been Manager of the General Study Department, Strategic Planning, Metro Director, and Chairman of the Operations Executive Committee, Luc moved to his current post as Senior Vice-President of Operations in 2011. Luc has also been Manager of the Special Study Department of STIB since 2013, and has been active in the International Association of Public Transport (UITP) since 1985.

Luc Derie is an electromechanical engineer and also holds an M.B.A. He joined STIB in 2013 having worked for many years at Bombardier Transportation. As Programme Director of STIB, Luc is in charge of modernising the Brussels metro system.

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