As a rail infrastructure manager, Infrabel is responsible for the rail infrastructure. This infrastructure consists of all fixed installations necessary to operate rail vehicles and ensure the safety of this traffic. Put simply these are: the rails, overhead lines, civil engineering work, signal systems, level crossings, etc. Rail infrastructure mainly consists of the following:
The rails and the track bed are the foundation on which the trains operate. Rails are made of steel and guide the wheels of the train. In Belgium, the standard track gauge is 1,435mm, measured between the interior surfaces of the railheads. They are laid on a surface of crushed stone, which is also referred to as ballast. This absorbs and distributes the load of the moving train across the surface so that the track always remains stable. The sleepers ensure that the rail width remains unchanged and transfers the load to the crushed stone. In the past sleepers were made of wood and railway lines consisted of short rails welded together. However, time doesn't stand still: now we build tracks with concrete sleepers and continuous welded rail without joints. The result: more durability, less noise, less vibration and more comfort.
2. Switches and crossings
Belgium has one of the busiest rail networks in the world. Train routes have to join and cross each other in many places. The switches and crossings ensure that all possible connections can be made. A switch consists of moving point blades that ensure a change in the train route. The switches are operated centrally from the signal boxes.
All rail switches and crossings are designed, manufactured and fitted in the workshop in Bascoup. This requires the highest level of precision work: a tenth of a millimetre makes a world of difference. The workshop in Bascoup supplies rail switches and crossings not only to the Belgian rail network, but also to a number of city transport companies and customers abroad. This video shows the production process for rail switches and crossings, i.e. from the moment of placing an order to the installation of the switches and crossings.
3. Signalling systems
Signalling systems are necessary to guarantee safety on the rail network. Thanks to these installations the train drivers receive the necessary instructions to operate the train safely. They ensure that trains do not collide and that the speed limit is respected.
While signals had to be manually operated in the past, most signal boxes now have modern technology which means that the signals are computer controlled. This EBP/PLP technology creates a route for each section and each train. The signaller can approve or alter the route, depending on the circumstances. This technology saves a lot of time and also assures safer railway traffic and more efficient rail traffic control.
In 2005, the railway network still had quite a number of local signal boxes. Infrabel is centralising these into modern traffic control centres, equipped with the most advanced technology. This will improve both safety and punctuality. Infrabel aims to reduce the number of signal boxes down to just 10 signalling stations by 2022.
The light signals are the communication channel between the signal operator and the train driver. The lights give the train drivers the instructions necessary to complete the train journey safely. They consist of a red light, a green light, two yellow lights and a single white light. They can also have an illuminated number and other indications.
Signal boards are fixed indications along the track enforcing speed limits.
Cab signalling gives the train driver all instructions on a screen onboard the train. The speed of the train is constantly monitored by these systems and the train is automatically slowed down if it is travelling too fast. These systems are replacing the signal systems along the track. In Belgium the ETCS system is being gradually adopted. Simpler versions of these systems have also been installed on the Belgian network and assist drivers in operating the trains: the crocodile, TBL1 and TBL1+ balises. These systems increase rail traffic safety.
4. Overhead lines
The overhead lines or power cables provide electricity to the trains. The train's pantograph is in contact with the power cable and thus provides the electrical current. In Belgium overhead lines are powered by the sub-stations with 3,000 Volts of direct current. For high-speed trains a current is used of 25,000 Volts of alternating current. The overhead lines consist of 2 contact wires that are tensioned by weights at the start and end of an overhead line section. To avoid the pantographs persistently being eroded where it contacts the contact wire, the wires are bent in a zig-zag pattern.
Sub-stations convert electrical energy provided by the suppliers into the desired voltage and distribute this energy across the rail network. Energy is supplied at high-voltage alternating current (11,000 volts to 70,000 volts) and is transformed to 3,000 volts direct current.
6. Civil engineering works
Civil engineering works are constructions that ensure that a railway line can bridge certain geographical features of an area and cross traffic routes without being hindered. They include bridges, tunnels and viaducts, but also retaining walls, culverts and underpasses, etc. The Belgian rail network has about 4,800 bridges, 2,500 retaining walls and 132 tunnels.
7. Level crossings
A level crossing is a junction of a railway line and a road on the same level. In order to guarantee the safety of the crossing traffic, level crossings have different safety features depending on the type of level crossing:
- St. Andrew's cross
- Ringing bell
If there is no rail traffic, the red light signals are switched off and the white light signals are switched on. The barriers are upright. As soon as a train approaches the level crossing, the red signal lights come on and the warning bell rings. The barriers come down. Once the barriers are closed, the warning bell stops ringing.
Infrabel is working to remove and replace as many level crossings as possible, as they pose a risk to careless road users.