Under the dramatically arching roof of Stratford Market depot, on the London Underground’s Jubilee Line, a team of engineers from Alcatel, a Canadian electronics company, is working at the control equipment hidden under the seats and in the cabs of one of the line's trains. They are checking it is still working safely after being the first train on the line to be fitted with new signal-reading equipment.

The work is one of the early stages of the introduction of a new signalling system which, when fully operational in 2009, will increase peak-hour capacity on the busy line – which serves the financial centre at Canary Wharf – 23 per cent by allowing trains to run faster and closer together.