Disgwylir i'r gwaith clirio ac adeiladu ddechrau yn 2019 a'i gwblhau erbyn canol 2022.  Bydd Trafnidiaeth Cymru'n caffael cwmnïau adeiladu trwy GwerthwchiGymru a fframwaith STRIDE.
Clearance and construction work is expected to start in 2019 and be completed by mid-2022, with Transport for Wales procuring construction companies through Sell2Wales and the STRIDE framework.