STORY: The railway, which has been renamed the "Elizabeth" line in honor 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).
The first passengers in line had been waiting since 5:00am (0400 GMT) for the first train set to depart at 06:33 am (0533 GMT).
Amongst the first passengers were London Mayor, Sadiq Khan, who joined passengers flooding into the station.
Chelsea Pensioner Peter Fullelove, 84, dressed in his red uniform, said the new line was very much for the Queen, ahead of her jubilee next week.
Sawyer Sarkadi-Smith, aged 11, was wearing his ‘mind the gap’ jumper - synonymous with London Underground - for his journey.
He said he’s been waiting to ride the train since 2016 and I loved trains “so much”. “It’s just a wonder”, he said.
Construction started more than 12 years ago on Europe's biggest infrastructure project at the time.
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.
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 has opened 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).