London's 10-year Crossrail program, which is one of Europe's largest infrastructure projects, is now due to open in the fall of 2019, some nine months later than planned. The project's infrastructure cost was increased by nearly $780 million this July to $20 billion.

The new railroad, known as the Elizabeth line, "is one of the most complex and challenging infrastructure projects ever undertaken in the U.K.," according to Simon Wright, Chief Executive of Crossrail Ltd, owned by the Dept. for Transport and Transport for London.

The 118-kilometer east-west line includes an all-new section with 21.5 km of twin tunnels through central London. Delays in fitting out new stations and tunnels in the central section have pushed back the commissioning schedule to late next year.

The project's tunnel work ended on time and budget just over three years ago. The first of eight TBMs had started work three years earlier.