Around £200M has already been spent on advance works ahead of construction of the phase three extension.
Two tunnels have been built to carry the tram at the Manchester Airport transport interchange and under Alan Turing Way in East Manchester.
Property demolitions and landscaping have taken place in Oldham, Wythenshawe, Ashton, Droylesden and Chorlton.
Bridges have been built to carry the tram over the River Medlock and road and railway lines near the City of Manchester stadium.
Construction of noise barriers to reduce environmental impacts in Ashton has also begun.