Transport for London has announced that the first section of new signalling set to transform almost half of the Tube network has begun operation.
The new Thales system, which will boost capacity on the Circle, District, Hammersmith & City and Metropolitan lines, is now operating between Hammersmith and Latimer Road, the first part of the network to benefit from the improvements.
The new signalling system will allow trains to run closer together from 2021, meaning the train frequency will increase in central London from 28 to 32 per hour.
Project completion is targeted for 2023, leading to a capacity increase of a third on the four lines.
TfL said that, although there is a chance of some short delays on the Circle and Hammersmith & City lines as the new system gets underway, so far it has been working well.