Brussels Regional Express Network
|Transit type||Commuter rail|
|Number of lines||8|
|Number of stations||120|
|Annual ridership||25,000,000 (projected)|
|Operation will start||2016|
|Number of vehicles||305|
|System length||350 km (217 mi)|
|Track gauge||1,435 mm (4 ft 8 1⁄2 in) (standard gauge)|
|Electrification||3kV dc overhead supply|
|Top speed||160 km/h (99 mph)|
The Brussels Regional Express Network (Dutch: Gewestelijk ExpresNet or GEN; French: Réseau Express Régional Bruxellois or RER) is a rapid transit system under construction in Belgium. It will offer fast connections and increased frequency within 30km of Brussels, covering a territory inhabited by 2.5 million people.
Most jobs in the Brussels-Capital Region are filled by workers from other regions. Private vehicles clog the city daily, hampering mobility and creating pollution. The RER/GEN is a response to these growing problems. Only 20% of commuters use public transport daily; the goal is to double this by facilitating movement into and within the city.
A first draft of the RER/GEN network was published in 1995. The commissioning of the first lines was then planned for 2002.
Construction requires the approval and funding from the federal government and the three Regions, as well as the collaboration of four public transit companies (NMBS/SNCB, STIB, De Lijn, and TEC). The initial work started in 2005, the commissioning of the network programmed for the year 2012. However, Belgium's administrative complexity caused numerous delays and postponements; the network will now be put into service in 2017.
Railway lines within a 30km radius of Brussels are included in the project. Parts of the project are already in place. The most substantial works relate to the quad-tracking of several lines: two tracks for GEN/RER trains, and two tracks for intercity and high-speed trains.
The RER/GEN project includes a 1.25km double-tracked Schuman-Josaphat tunnel in the north east of the city. This will link the European Quarter to Brussels Airport, cutting journey times between the two to 13 minutes.
Most of the network uses existing rail lines. Increased frequencies and passengers, however, requires in addition to the Schuman-Josaphat tunnel, other significant infrastructure projects:
- Quad-tracking of sections in order to segregate local and regional traffic from faster inter-city trains
- Demolition and reconstruction of several bridges that cross the wider track
- Construction of additional breakpoints
- Installation of noise barriers
- Redevelopment of 28 existing stations in Brussels
- Creation of transfer points
- Construction of park-and-ride lots
Rolling stock 
NMBS/SNCB has ordered 305 Siemens Desiro ML single-deck electric multiple units, a €1.425bn contract. These will have a 2MW power rating and a capacity of 280. The deal represents a break from NMBS/SNCB sourcing its stock from Bombardier, with construction announced as being at Siemens' plant in Germany.
According to the NMBS/SNCB website, the GEN/RER will have nine lines. Their website currently shows a network plan foreseen for 2012. The map numbers eight lines, while a ninth line (Wavre - Villers-la-Ville) is depicted but not included in the map legend.
|1||Zottegem / Geraardsbergen ↔ Brussels ↔ Arenberg||37|
|2||Nivelles ↔ Brussels ↔ Louvain-La-Neuve||31|
|3||Braine-l'Alleud ↔ Brussels ↔ Brussels Airport ↔ Leuven||19|
|4||Geraardsbergen ↔ Halle ↔ Brussels ↔ Mechelen||33|
|5||Laeken ↔ Aalst||18|
|6||Braine-le-Comte ↔ Brussels ↔ Dendermonde||23|
|7||Halle ↔ Brussels ↔ Vilvoorde||16|
|8||Aalst ↔ Brussels ↔ Louvain-La-Neuve||18|
|9||Villers-la-Ville ↔ Ottignies ↔ Wavre||9|
2009 plan 
The plan envisages a direct link between Ottignies and Leuven in 2015, with a service between Dendermonde and Mechelen and a connection to Gosselies airport (Brussels South Charleroi Airport) in 2020. Further possibilities for expansion are proposed for 2030.
See also 
- (French)Le journal du RER
- "Le RER en lignes" (in French). NMBS/SNCB. Retrieved 2010-12-31.
- "Carte du réseau RER". NMBS/SNCB. Retrieved 2010-12-31.
- "Réseau Express Régional de Bruxelles" (in French). Significance. Retrieved 2010-12-31.
- "Evolution et optimisation du Réseau Express Régional de Bruxelles et de ses environs" (pdf) (in French). 2009-06-22. Retrieved 2010-12-31.