The order comprises six pre-series vehicles and 130 production cars and will be a direct replacement for the existing train fleet, which dates back to the opening of the network in the early 1980s. The new trains will be equipped with LED lighting, Wi-Fi, CCTV, and bicycle racks and will be assembled by AnsaldoBreda at a plant in the Miami area.

A selection committee chose AnsaldoBreda as preferred bidder for the contract last year, but the decision was the subject of a legal challenge by CAF, which filed a lawsuit locally claiming the county had breached federal procurement law by favouring AnsaldoBreda because it would assemble the trains locally.

The court subsequently ruled against CAF, but its complaint was upheld by the Federal Transit Administration and the tender process was restarted, this time without attributing value to local assembly.