Inside Australia's biggest transport project

That's how one of the early architect's of the Sydney metro project describes the seven futuristic stations of Sydney's new metro line.

The $21 billion line from Chatswood to Sydenham officially opened in August.

Matthew Pullinger, whose firm Matthew Pullinger Architect, was involved in the design leadership of the project told ACM it was a "massive undertaking".

"These new stations are like cathedrals of the 21st century," he said.

"Sydney has just built seven of these underground cathedrals - with all the scale, expressive structure and spatial drama we associate with a cathedral."

He said just as cathedrals do, the metro line will serve as "emblems of our shared civic pride".

"They aim to inspire and lift the spirit of those who move through the city every day as citizens or visitors."

Mr Pullinger said each of the stations have their own individual flair, existing more like "distant cousins" than "identical twins".

This differs from most previous transport projects.

Different architects and developers brought each station to life.

Also, unlike other transport projects, many of the stations include either a residential or office building above the station as a way of offsetting the cost of the project and assisting broader renewal and growth of the city.

Crows Nest, Waterloo and Gadigal stations include residential buildings, with Waterloo home to 3,000 new social housing apartments that will be at the "front door of the new station".

"In this way, the new metro goes well beyond being a transport project and serves as a stimulus for major urban renewal, improving the equity of access to jobs, cultural, entertainment and education opportunities that the city offers in the way that is incredibly important to the social sustainability of the city," Mr Pullinger said.

Other stations offer expanded office space above the station entries with the Martin Place and Gadigal stations "consolidating the Sydney CBD's role as a major global hub for international investment and high value jobs".

In contrast Central station and Barangaroo don't have an over-station development.

Instead, Central is at the heart of the transport network, an interchange with other modes of transport such as light rail, buses, suburban rail and regional trains, Mr Pullinger said.

The new metro line boasts 16 stunning public artwork pieces across many of the new stations with a trip to admire the aesthetics worth it alone.

The Sydney metro superhub Martin Place station features the most iconic artworks including a fascinating heritage piece from 1962 by the late Douglas Annand and an immersive light display connecting the old and new station.