of improvements in prior years; according to industry periodical Rail, it was the second least subsidised passenger operator by 2015. Rolling stock Greater Anglia inherited a fleet of , Mark 3 carriages, Driving Van Trailers, , and diesel multiple units, and , , , and electric multiple units from National Express East Anglia. Due to its short initial franchise term, Greater Anglia was not planning to introduce any new trains, although this policy changed substantially following the start of its second franchise term in October 2016. In November 2013, an online petition was launched, aimed at stopping Greater Anglia's trains from dumping raw sewage from the train toilets directly onto the tracks. There were also concerns with the 'sewage mist' from passing trains making Network Rail staff ill, and Greater Anglia announced it was "working closely" with the government to introduce a fleet upgrade. By October 2016, all the franchise's Mark 3 carriages and Class 156 multiple units had been refitted with controlled emission toilets. On 31 May 2015, the company's fleet of Class 315 trains were cascaded to London Overground and TfL Rail, and some Class 317 trains have been cascaded to London Overground, which has taken over local services in North and East London from the Greater Anglia franchise. In August 2016, it was announced 1,043 new carriages would be purchased, which will allow for all of the ageing stock to be replaced, especially necessary given that a number of coaches are not compliant with accessibility requirements beyond 2020 and they would not be able to meet Abellio's new targets for lower journey times without extensive modification. One part of the contract went to Bombardier with nearly £1 billion to build 111 Bombardier Aventra electric multiple units and the other part of the purchase went to Stadler to build 58 FLIRT electric multiple units, all of which would enter service between August 2019 and September 2020. Bombardier's order included all 111 Class 720 units for taking over local and commuter services out of Liverpool Street. Stadler's order included 20 twelve-carriage Class 745 units for taking over intercity services on the Great Eastern Main Line and the Stansted Express as well as 38 three- and four-carriage Class 755 units for taking over all local diesel services from the previous outdated rolling stock. By July 2020, all Class 755 trains have entered passenger service. The first unit of the new