sentences:  When first used in service, the units suffered a fault with engine vibration in the passenger cabin, which has since been rectified.The units were originally meant to replace all of the Class 150s, however three were retained.Between late 2018 and early 2019 West Midlands Railway, operated by West Midlands Trains, inherited the London Overground 172/0s to replace the remaining Class 150s for transfer to Arriva Rail North and Class 153s operating on the Coventry–Leamington line and the Coventry to Nuneaton line as well as providing extra capacity in Snow Hill Line.