The Invitation to Tender (ITT) for the New Tube for London project, which will provide 250 new trains for the Bakerloo, Central, Piccadilly and Waterloo & City lines, has been delayed until December 2015.

The ITT was originally due to be issued at the end of February, but the delay has been confirmed in TfL’s Budget for 2015-16. The slippage has also been linked to the delay in the resignalling of the Sub-surface Railway lines, the completion date for which has been pushed back from 2018 to 2022.

London Underground says that costs have risen by 30% to £5.54 billion for the modernisation of the Circle, Metropolitan, District and Hammersmith & City lines. It is in the final stages of negotiations with Thales (a french multi-national company that designs and builds electrical systems) to implement Automatic Train Control via a version of its Seltrac transmission-based moving-block signalling and control system, which is in use on the Jubilee and Northern lines.