When the train pulls into COOVI station, the figures in Marin Kasimir's photographic panorama seem to press in through the windows. And when you step out of the carriage at Graaf van Vlaanderen, life-size human figures suspended high above the rails appear to be caught in an act of collective suicide. Even though the work is called “16 x Icarus”, I'm not entirely sure that this is the effect artist Paul van Hoeydocnk had in mind.

There are works of art in most of the metro stations in Brussels, thanks to a policy that began with the birth of the network in the late 1960s. The idea was that art would contribute to the broader aim of having an open, welcoming transport system in which each station had its own identity. Another goal was to bring contemporary art to a public that would not necessarily seek it out in museums and galleries.

Evidently, it is hard to achieve all of this at the same time. For example, Stokkel station has a strong visual identity thanks to its parade of characters from the Tintin comic strip, but this is hardly contemporary art. At the other extreme, Félix Roulin's "Sculptures" at Thieffry is impeccably contemporary but seems to be in the process of consuming passengers rather than welcoming them.

Sometimes you have to actively search for particular pieces, either because they have been tucked away in obscure passages or blend into the background (is it geometric abstraction or just coloured tiling?). But art spotting on the metro is addictive, and there are lots of pieces that are well worth lingering over or travelling out of your way to see.

Deciding what gets in

Choosing art for the metro was initially the job of the national communications ministry, advised by an artistic commission. When the Brussels Capital Region was created in 1989, it became the responsibility of the regional transport minister, who established a new set of advisors, the Artistic Commission of Transport Infrastructures.

This commission has a dozen or so members, most from the art world, including critics, historians and museum directors. There are also representatives of MIVB, which runs the metro, who advise on technical questions and ensure that the art doesn't interfere with passenger safety or train efficiency.

The process of commissioning a work, from the first discussions to its inauguration, typically takes around two years. The first step is for the members of the commission to think about which artists they would like to invite to propose a work for a particular site. A series of meetings then takes place, during which each artist discusses his or her ideas and presents previous work and proposals for the station in question.

Technical limitations and cost are taken into account, but generally this is done after the conceptual questions have been answered. Once a single candidate is selected, the recommendation is passed to the minister for a final decision.

According to Gita Brys-Schatan, president of the commission and founder of the ISELP art institute in Brussels, the focus is on experienced artists, although younger people may be included if their work has reached a certain maturity.

“Our two main principles are the experience and merit of the artist and if the artist is able to propose a project that relates to the history and sociology of the neighbourhood in which the station is located,” Brys-Schatan explains in a telephone interview. “One wouldn't do the same thing, for instance, in one area where there are luxury boutiques and another where there is a strong immigrant community.”

Examples where she thinks this local focus has worked particularly well include Jan Vanriet's "De stad beweegt in de palm van mijn hand" ("The city is moving in the palm of my hand") at De Brouckère, which reproduces visual elements from the neighbourhood, past and present, along the walls of a passage with a moving walkway. Then there is Vincen Beeckman's "Casting" at Anneessens, which covers columns on the platform with a montage of photographs taken in the homes of people living nearby.

And at Noordstation there is Johan Muyle's massive fresco "I promise you ('r) a miracle", which includes portraits of 43 contemporary personalities from the arts, theatre, music, literature and cinema. "It's a work that speaks directly to the public and at the same time represents the location – because it's a place of transit, a place of arrival," says Brys-Schatan. "The artist wanted to show everyone who passes through that these are the personalities of our culture."

Art vs politics

The accessibility of the art is something that is balanced across the network, with easily understood work in some stations allowing the selection of challenging work elsewhere. This is the only aspect, however, where the commission has been able to take a broad view. "After a certain number of years we tried to develop a collective policy – a programme that included the whole of the territory," Brys-Schatan explains. "Unfortunately, it turned out to be impossible because each of the 19 communes has its own hegemony."

As for the ministers, they have accepted the vast majority of the commission's selections. Occasionally, though, they have rejected quite well-known artists or insisted on an artist that the commission doesn't like. (Brys-Schatan is too discrete to name names.)

At present, the future of art on the metro is unclear. There are new works still to be inaugurated, but the commission has been put on hold for the past year while the current transport minister, Pascal Smet, considers whether or not he wants to continue with arrangements as they stand. The assumption is that change is in the air, as indeed it is at Belgica station, where a display about the effects of global warming is being installed, rather than a work of art.

Five top stops

Merode "Ensor: Vive la Sociale" (1978) by Roger Raveel

Raveel asks "What did Ensor mean by 'Vive la Sociale'?" referring to a banner in James Ensor's celebrated painting "Christ's Entry into Brussels". The work, which also references Jan Van Eyck's "Lamb of God", provides a fascinating connection with Raveel's Flemish artistic forebears, while proposing a view on society with characteristic touches: a mirror embedded in the painting, a self-portrait, concrete walls and faceless men in flat caps.

Hermann-Debroux "The Fall of Troy" (1978) by Jan Cox

Originally at Rogier, there is something appropriate about this painting's more recent home at the end of line 1B, mounted above a tunnel through which only empty trains pass. The shapes of ramparts, a horse and a woman's face half-hidden in Cox's fiery colours suggest a distant world of myth, accessible beyond the frontier of the network. But as a warning, there are also a skull and the setting sun.

Naamespoort "Het uiteindelijk Verkeer" (1979) Octave Landuyt

The Flemish artist’s huge ceramics suggest four phases of life – birth, love, adulthood and death – but to my eye there is something funereal about all of them. They are like giant memento mori, finding death in life and putting it under glass. Yet these hands and faces, like details from a Richard Dadd painting, also have a mesmerising gothic elegance that blends perfectly with the shining surfaces of the ticket hall.

Aumale "Metrorama 78" (1982) by Jean-Paul Laenen

The long platforms of the metro lend themselves to panoramic images, and here sculptor-turned architect Laenen has reconstructed the local neighbourhood with images supplied by the MIVB photographic club. In one direction, the Mechelen-born artist has reproduced the scene of the station under construction, with roads dug up, piles of earth and cobbles everywhere, and houses braced for demolition. In the other direction, there is a more fragmented collage of images evoking local life in the 1970s.

Het Rad "De Cyclus van het Rad" (2003) by Denis De Rudder

In "The Cycle of the Wheel", the Brussels artist provides a different sort of panorama, with eight views of the neighbourhood painted in sinuous strips representing the wandering gaze of the viewer. His flat, realist paintings take us seamlessly from the rooftops to road works, from trees to the water in a canal. The more you look, the more the transitions draw you in. And on the ceiling, a similar view of the trees overhead.