In 1980 the city of Antwerp started building the metro line from Antwerp Central Station to Deurne. The route was proposed from the south-western suburbs via stations Opera and Astrid to then eastern suburbs.

Some of this line was built but construction stopped in the 1980s due to lack of funds.

Under the Pegasus plan, approved in 2004, several tram lines will be built to the eastern suburbs, using some of the tunnels abandoned in the 1980s, including stations at Opera, Astrid, Drink and Morkhoven. So probably the lines will be in use after 30 years!

Info wikipedia.org
Thanks to Arno