Adelante units, operating on the Great Western Main Line, but following technical issues they were transferred elsewhere. In 2012, five units were returned to First Great Western to operate weekday services on the Cotswold Line, allowing class 165 and 166 units to be reallocated to increase capacity on Thames Valley services. The Class 180s left GWR in stages between June and December 2017 to join Grand Central. The 150/1s in the GWR fleet transferred to Arriva Rail North in stages, beginning with the first three in August 2017 when their leases expired, and ending in April 2018. The 153s also transferred elsewhere in stages too, with the first four units going to East Midlands Trains and the next five units going to Arriva Rail North. This left just five 153 units with GWR, which eventually transferred to Transport for Wales in April 2019. Rejected fleet It was planned for Great Western Railway to operate nineteen Class 769/9 units once they were fully rolled out. The operator intended to run the first services in spring 2019, but this was delayed by issues faced by Porterbrook in converting the units. However, the first vehicle has been delivered and all were expected to be delivered by the end of 2021. Although initially planned for use in London and the Thames Valley, while 12 units were modified for Heathrow Express services, the future plan for these units was to be operating on services between , and , which would have meant operating on non-electrified OHLE and third-rail routes. To enable this, GWR's allocation of Class 769 units would have retained their dual-voltage capability in addition to being fitted with diesel power units. The units would also receive an internal refurbishment and be fitted with air cooling. The first Class 769 to be delivered to GWR was unit 769943, which arrived at Reading TMD in August 2020. It was expected to enter service in early 2021. The Class 769 was expected to enter service with GWR between June and December 2021, but this was later delayed to 2022. In December 2022, GWR announced that the introduction of the Class 769 fleet would be abandoned and the units handed back to Porterbrook in April 2023. Livery Great Western Trains adopted a livery of dark-green upper body and ivory lower body, with a stylised 'Merlin' bird logo. Following the rebranding as First Great Western, fader vinyls were