61 units at a cost of £60 million. This commenced in mid-2004 with the ex-First Great Eastern examples, and included the full replacement of door operating mechanisms, passenger windows, and seat covers, substantial replacement of floor coverings, and the installation of CCTV. Greater Anglia The Class 315 fleet transferred to new operator Abellio Greater Anglia in February 2012. Abellio repainted the trains in its own livery and commissioned Bombardier to refresh the fleet, which included installation of a new passenger information system with electronic dot-matrix display screens, installation of bays for two wheelchairs and assistance intercoms for passengers in those areas, and accessibility changes to the handrails and inter-car gangways. Abellio used the fleet for local services between to on the Great Eastern Main Line (the 'Shenfield Metro' service), and between Liverpool Street and , , and on the Lea Valley Lines. They were also used on the Romford–Upminster line, alongside Class 317 units, as well as occasional peak-time services to destinations further from London on the Great Eastern and West Anglia Main Lines such as , , , and . Initially, the Shenfield Metro and Upminster branch line services used only units 315801–315843 and the Lea Valley Lines only 315844–315861, reflecting the allocations of the former franchises, but they were later operated interchangeably out of Ilford EMU Depot. Elizabeth line The remainder of the fleet was operated by MTR Elizabeth line, who used them for a small number of Elizabeth line services on the Great Eastern Main Line between London Liverpool Street and Shenfield as a continuation of the previous TfL Rail operation. A farewell tour for the class organised by the Branch Line Society was announced in October 2022 and took place on 26 November. The last day of service for the Class 315 units was 9 December 2022. Replacement In July 2015, TfL confirmed that it would place a £260million order for 45 units of Class 710 Aventra trains, which would replace London Overground's Class 315. The Aventras would be introduced on the West Anglia routes in 2018, having taken these over from Abellio Greater Anglia in May 2015. The first units on the Lea Valley lines entered service on 3 March 2020, after a first attempt on 24 February 2020. They replaced all Class 315s on both the Lea Valley lines and the Romford to Upminster branch in October 2020. Additionally, TfL Rail Class 315 units