At the time of the vehicles withdrawal, there was the threat of strike action by power workers. As a precaution, one of the original WR power cars was stabled in Bristol Temple Meads as a standby generator.
Alan Rushworth adds -
regarding the time when the power cars were used as generators: W60731 was at Bristol Temple Mills and W60648/9 at Cardiff. One power car was retained at Bristol Temple Mills for use as an emergency generator during industrial disputes involving the power and coal industries in Dec '73. In Jan '74 W60093 andW60731 were in use at Bristol Bath Road as emergency generators whilst W60096 and W60647 were at Bristol Temple Mills platform 4 for the same purpose, they remained there until Jul '74.