By 1974 the northern WCML was electrified, and the Class 50 fleet was displaced by new Class 87 electrics. The fleet was transferred to the Western Region between 1972 and 1976, working mainline passenger services from London Paddington along the Great Western Main Line (GWML) to destinations such as , Bristol Temple Meads, and . It was not unusual for locomotives to work services on other routes, such as the Birmingham New Street to Bristol Temple Meads corridor. The introduction of the Class 50s on these routes enabled the last remaining, non-standard, diesel hydraulic "Westerns" to be withdrawn.