Work at the Canary Wharf Crossrail station took a major step forward with the turning on of the site's dewatering pumps by the UK's Transport Minister, Sadiq Khan.
The pumps will drain nearly 100 million litres - the equivalent to 40 Olympic swimming pools - from the worksite over the next six weeks.
The water will be transferred from inside the site's specially constructed coffer dam to the North Dock at a maximum rate of 13500 litres per minute.
The station box will then be constructed inside this dry environment.
Over the next six weeks, 98 million litres of water will be pumped through twin 152 mm-diametre pipes inside the coffer dam to reveal the future scale of the new station. As the water level lowers, pumping will temporarily stop to enable engineering adjustments to the coffer dam.
Once the water level drops to approximately 1 m above the dock bed, specialist contractors will move into the dock to safely remove and relocate any fish and aquatic life that might be present.
Canary Wharf Group is designing and constructing the station on behalf of Crossrail. The enabling and civil engineering works are delivered by Expanded, a subsidiary of Laing O'Rourke.
Commenting on progress to date, Crossrail chief executive Rob Holden, said, "Construction of Canary Wharf Crossrail station has made significant progress since work got underway in May last year. Draining of the coffer dam at North Dock will reveal the true scale and extent of the new station, the biggest on the Crossrail route.
"Work on Europe's largest construction project continues apace elsewhere with preparatory work now underway at the Royal Oak tunnel portal site and also at Farringdon, Paddington and Tottenham Court Road. Construction at the remaining stations on Crossrail's central section will begin later this year."