Metro Transit awarded Siemens a contract in 2010 to supply up 109 S70 LRVs, with an initial order for 31 vehicles for the Green Line and 10 to expand the Blue Line fleet. In 2013 Metro Transit exercised an option for 18 additional S70s and at the end of September it took up a second option for five more vehicles. This means the agency still has options on 45 more Siemens vehicles.

Additional LRVs will be required for the extension of the Green Line from Target Field to SouthWest Station, which is due to open in 2020 and the Blue Line extension to Oak Grove Parkway, which is scheduled for completion in 2021.