When was this line built, and why was it abandoned? Something similar happened in San Jose, California: around 2000 they built one more light rail line, to Almaden, probably with use of an abandoned railroad, but a few years ago abandoned that line, too. But it is just a mile, about 1,5 km, long.

Когда была построена эта линия, и почему была заброшена? Нечто похожее случилось в Сан-Хосе в Калифорнии: году в 2000 построили ещё одну линию как бы трамвая, light rail, похоже, по трассе заброшенного подъездного ж.д. пути, но несколько лет назад забросили её тоже. Но она всего милю длиной, порядка 1,5 км.

The metro plans in Belgium were planned simultaneously from the 1970s onwards. The works started at about the same time everywhere and also the first inaugurations were already at the end of the 70s/early 80s. The plans (everywhere in Belgium) were very ambitious. All that came to an abrupt end when, in the mid-80s, it was decided that the regions would have to finance such works themselves.
The result is well known: in Antwerp a tunnel and stations have been waiting to be finished and put into service since this period, in Liège, work has started on a metro, and what is there has finally been used to store old buses...

This part was and is completely finished until Centenaire. After that, the structural work was done, but it was never finished. The plan makes it a little clearer.
https://transphoto.org/photo/1569376/?gid=2715
The inauguration was therefore planned for 1985 and was cancelled a few days beforehand.

The reason was disagreement between the two operators at the time, with one company using trams in the area of the other company using buses, and they were completely unable to reach agreement on the distribution of costs/revenues. 5 years later, they were merged, but 1. the mutual distrust was still not overcome and 2. they came to the conclusion that the exploitation costs would be very high, higher than the few buses per hour that are running in the area...

Ultimately, Europe will contribute to the further development (and reconstruction) of the infrastructure.
Of course, nothing is known about the operation. The network plan was made by Public Relations, nothing more. Whether there will be a line 5 is not at all certain, and it is possible, for example, to run the existing line 2 up to Les Viviers - and change the entire tram network at the same time.

I will post other photos, including those of the never-finished infrastructure, in the near future.

Thank you for such detailed but sad story. Since I've heard about these metro-stations in Charleroi for the first time in mid-2000s, I couldn't guess reason for decision not to start operation.

That the works are finally starting now is thanks to Covid-19. Europe has provided a budget for ecological purposes for all member states. Wallonia will use it for tram projects in Charleroi and Liège, Flanders got much less but will use the money to renovate (and isolate) outdated school buildings.

I took the opportunity to post another picture, which totally fits the local curiosity cabinet.

https://transphoto.org/photo/1867388/

I don't want to go below the red line, but if you know that at one point, half of the city council was in jail for corruption, then everything is also said....