London Tube delays 'will decline as lines upgraded'
Further repairs to the Tube network will not cause the same level of disruption seen during the Jubilee Line upgrade, the managing director of London Underground (LU) has said.
A strategy for improvements on other lines will minimise delays and cancellations, Mike Brown added.
Stations on the Jubilee Line have been shut on more than 100 weekends in four years to replace signalling.
In November LU promised work on the line would finish this spring.
"We're now reconfiguring the programme for upgrading the Northern Line and it will be an entirely different way," Mr Brown told BBC One's Politics Show London.
The tendering process for new systems on the District, Metropolitan and Circle Lines specified "no closures for the signalling upgrade", he added.
"I'm determined to see this through in a way which is much less disruptive to London."Delays 'debacle'
Transport for London (TfL) has claimed 95% of scheduled Jubilee Line services ran in 2009-10.
The Politics Show London calculated that when weekend shutdowns were added to the figures, however, only 78% of trains ran in that period.
Professor Tony Travers of the London School of Economics said "the closures were removed from the statistics as if somehow they don't happen".
But Mr Brown said: "You cannot transform an ancient Tube network without some closure.
"You can't run tracks that you're taking away to replace with new tracks."
The Jubilee Line upgrade was launched by maintenance firm Tube Lines but was passed to LU last year, when it took over the company.
The delays were branded a "debacle" by the office of London's mayor, Boris Johnson.
A separate upgrade for the Northern Line was delayed as it was due to follow on from the Jubilee Line work, and is now due to open in 2014.