Piccadilly line upgrade 'to blow £3billion budget' as passengers told not to expect new trains for a year

TfL chiefs warn of ‘major challenge’ integrating new high-tech trains with ‘extremely old infrastructure’

Piccadilly line upgrade 'to blow £3billion budget' as passengers told not to expect new trains for a year

TfL chiefs warn of ‘major challenge’ integrating new high-tech trains with ‘extremely old infrastructure’