There will now be a standstill period of at least 10 days before the contract for 1140 Siemens Desiro City emu vehicles can be signed.

Siemens was unveiled as preferred bidder for the contract on June 16 2011, two years after the Private Finance Initiative (PFI) contract was originally due to be signed, and the process has suffered delays ever since. A report published last week by the National Audit Office warned that delays in rolling stock procurement represented a significant risk to the overall delivery of the £6bn Thameslink programme, which is due to be completed in 2018.

According to the report, the DfT still expects Siemens to deliver the first trains by December 2015, just two-and-a-half years after the contract award date. Siemens told IRJ recently that it had already invested a considerable sum in design work to ensure it will be ready to start production when the contract is signed.

The trains will be assembled at Siemens Krefeld factory in Germany and operate in eight or 12-car formations.

The delivery of the Desiro City fleet will allow the transfer of the existing fleets of class 377 and class 319 used on Thameslink services to other routes, including newly-electrified lines west of London and in the northwest of England.