Japanese company Hitachi has won a 2.2-billion dollar contract to build a new model of railcar for Washington DC’s subway system.

The transit authority in the US capital wants 800 railcars from Hitachi, which plans to construct a new factory there to start delivery in 2024. It marks the largest-ever contract for the firm’s US railway business.

Railways are a key revenue source for Hitachi. In 2015, the firm acquired an Italian railcar business as it pushed to expand in Europe and North America.