Station box

Poured concrete or pre-cast panels are then used to form the various levels and internal structures, similar to the construction of the underground basements of high rise buildings.

When the construction is complete, this station box is covered again up to the street level.

At the end of excavation, a similar result to the "bottom-up" method is obtained – with the concrete slabs and supports for the various levels of the station already constructed.

Station box construction methods have been used in a wide variety of subway and metro projects.

Examples include Crossrail in London, UK;[4] the Toronto–York Spadina Subway Extension in Toronto, Canada;[5] Sydney Metro in Sydney, Australia[6] and the Thomson–East Coast Line in Singapore.