London's long-delayed and over-budget Crossrail finally opens to passengers on Tuesday, offering faster journeys from Heathrow Airport and Berkshire in the west to Essex in the east through a series of new, long tunnels under Britain's capital.
The railway, which has been renamed the "Elizabeth" line in honour of Queen Elizabeth, is expected to carry 200 million people a year and will increase London's rail capacity by 10%, according to Transport for London (TfL).
Construction started more than 12 years ago on Europe's biggest infrastructure project at the time. In 2010, the project was budgeted at 14.8 billion pounds and was set to open in December 2018.
Delayed by issues with safety testing and signalling systems, even before the onset of the pandemic, Crossrail will open three and a half years late and more than 4 billion pounds over budget for a total cost of 18.8 billion pounds ($23.6 billion).
TfL Commissioner Andy Byford said the opening day was set to be a truly historic moment for the capital and the country.
"We look forward to showcasing a simply stunning addition to our network," he said earlier this month.
Initially 12 trains per hour will run in each direction through the middle section of the line, which includes 21 kilometres (13 miles) of tunnel, linking Paddington in the west to Canary Wharf and Abbey Wood in the east.
The first services on Tuesday will depart at 6:30 a.m. (0530 GMT) from Paddington and Abbey Wood.
Later in the year, the central section will be connected to branches in the west and the east, allowing services to nearly double, TfL has said.