STIB, the public transport body in Brussels, has awarded a framework agreement for up to 175 trams to Bombardier.
A firm order for 60 vehicles, valued at around €169 million, will be placed initially.
Bombardier, which built the city’s 2000, 3000 and 4000 series trams, will design, manufacture and maintain the new vehicles.
The contract specifies both 32 metre and 43 metre vehicles.
2017 was a record year from STIB’s tram network, with an 8 per cent increase in ridership.
As well as keeping up with demand across the network, the new trams are needed for the new line 9, an extension of line 94 and to increase capacity on line 81.
Bombardier will deliver the new trams from spring 2020, where they will undergo testing before entering passenger service.