Mobility (PRM) requirements so that the fleet could be operated beyond 1 January 2020; this work involved the expansion of space allocated to passengers using wheelchairs, the installation of wider internal doorways, and the toilet areas being rebuilt to be fully accessibility-friendly; toilet retention tanks were also fitted at this time. During late August 2018, the first PRM-compliant Class 158 was introduced by ATW. On 14 October 2018, the Class 158 fleet was transferred to the new operator Transport for Wales. During February 2019, the first unit was seen in Transport for Wales colours. As early as 2018, it was being reported that Transport for Wales were planning to replace its Class 158s with newly-built Class 197 multiple units by 2023. East Midlands Railway The Class 158 Express Sprinter Units were introduced to the East Midlands by Regional Railways Central to replace the Class 156 SuperSprinter on long-distance express services branded as Alphaline, such as to via . Following privatisation, Central Trains operated these services but quickly procured a large fleet of Class 170 Turbostar units for such services and transferred the Class 158 fleet to secondary routes such as to and to . East Midlands Trains (EMT) had a fleet of 25 units inherited from Central Trains, with some units transferred from First Great Western and South West Trains. EMR's Class 158 Express Sprinter units operate long-distance express services (such as Norwich to Liverpool) and secondary non-express workings such as Nottingham to , Nottingham to Matlock and to . The hourly Norwich to Liverpool service has been criticised for overcrowding, especially between Liverpool and Nottingham. This resulted from the Department for Transport specifying two-coach units in the EMT franchise starting in November 2007. In the light of persistent and excessive overcrowding, with some passengers being left behind on occasions, the DfT eventually admitted that it had made a mistake. Various cascades of other units enabled more Class 158 stock to be released for this route, and from the December 2011 timetable change the busiest services have been lengthened to four-coach trains between Liverpool and Nottingham, with units splitting and joining at Nottingham as necessary, two-coach trains being regarded as adequate between Nottingham and Norwich. Further services on this route were strengthened from December 2012. During May 2015, 158889 transferred to EMT from South West Trains on a two-year loan. This allocation was then made permanent in August 2017 following