UNPREDICTABLE HUMAN factors such as bewildered tourists and confused commuters have been blamed by London Underground for the total withdrawal of Circle Line trains for eight weeks.
Chaos ensued on Monday 14 June following the closure of the Circle Line tunnel between Gloucester Road and High Street Kensington, to allow nine weeks of major strengthening works to begin (NCE 22 April).
LU had hoped to run Circle Line services over District Line tracks. However, a signal failure on the first morning saw the complex emergency timetable collapse, and Circle, District and Metropolitan Line trains were backed up right across the network.
According to a LU spokesman, the key factor was a significant increase in 'dwell time' - the time between train doors opening and doors closing.
'At Westminster and Embankment, for example, dwell time usually averages 23 seconds,' he said. 'Last Monday it shot up to more than 40 seconds. Delays snowballed until trains were backed up across the Aldgate junction, completely blocking Metropolitan Line services.'
A higher than expected number of 'irregular travellers' was one factor increasing dwell times, the spokesman added. Regular District Line travellers were also said to be confused by the presence of Circle Line trains on the line, which added to the delays at stations.
LU's first response was to withdraw Circle Line trains during peak afternoon periods. All Circle Line services were suspended last Friday while LU tried to work out an alternative timetable, but the attempt failed.
LU said this week the nine- week closure of part of the Northern Line's Bank branch from 3 July 'shouldn't have too much of an impact'. A spokesman said there would be extra trains on the Charing Cross branch and a 'much enhanced 133 bus service' along the closed section of the route.