Boris Johnson has arrived at the Bombardier factory in Derby to inspect the progress on trains being built for London's Crossrail project.
The contract with Transport for London is worth £1.3bn.
Bombardier is delivering 65 nine-car trains for the east-west rail link in the capital.
The project is due to open in 2018.
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Chilly start, with bright or sunny spells.
Chilly start. Fine and dry.
A three-year-old is among five people who were injured in the crash in the Erdington area of Birmingham