Severe delays plaguing the Jubilee and Metropolitan lines this week could continue for some time after London Underground admitted it has been unable to solve two separate IT problems.
A notice to customers from John Self, general manager Jubilee Line, posted at Swiss Cottage tube station, apologised to customers for "the severe delays".
It blamed "a computer system failure which resulted in loss of control of the signalling system from Baker Street", and said "manual control was quickly introduced."
At fault were two GEC4190 computers running the Baker Street control centre. They have recently been upgraded to extend the range of the computer so it covers the Metropolitan Line as far as Aldgate and Farringdon, said a spokesman for London Underground. This upgrade has caused "glitches", said the spokesman
"The system failed and the computer went down at 7am so people were used to operate signals manually. Initially they thought it was the millennium bug," he said.
However, after further investigation London Underground found that it was code problems in the software used to upgrade the GEC computers.
London Underground said the work involved in "deglitching the additional parts" should be finished within weeks or "months at worse".
When asked if this could mean further delays, he said: "Who knows? With deglitching it is always a possibility."Steve Mowbray, Unix system administrator at Heriot-Watt University, had extensive experience with GEC4190 computers at Manchester University, which, he said, ripped them out seven years ago because they were too old.
"I'm not sure why anybody is using these big old boxes. They are clunky, and a desktop PC is more powerful than one of those," he said.
However, analyst with Bloor Research, Martin Brampton, said, "Unless they do a radically different requirement today, then there is no good reason to rip them out."
The other IT problem relates to the signalling system, which was much-publicised when it contributed to delays on the Jubilee Line extension. The chief executive of London Transport, Denis Tunnicliffe, told the culture committee before Christmas that a more robust signalling system is necessary for the new Jubilee Line extension.
Two signal boxes are used to run the Jubilee Line between Stratford and Stanmore, but there are "problems in getting the correct signal information from Neasden centre at the western end to control the new line between Green Park and Stratford," said the LT spokesperson.
"Engineers are working on it," he added.
Until then, the line will be "failsafe, but the service will not be reliable," he said. "It's quite a serious matter."
Additional reporting by Andrew Craig
Comcast's £29.7bn winning bid more than twice the £13.7bn Rupert Murdoch valued Sky at just eight years ago
A nuclear strike has been considered, but Bruce Willis is nowhere in sight
Spray-on antenna could enable seamless integration of antennas with everyday objects
Parker Solar Probe, TESS and GOLD missions will deliver exciting data, claims NASA