I was watching a streamer on Mixer and he was driving a class 166 and it lost all power, he stopped the train and managed to restart it but after it got to 40+mph the engine cut out again, This happened several times and he eventually left the train and took over another but the same fault occurred there as well. He has driven this type of train several times and not had the problem before. He will post here about the problem later and asked me to post as a witness.
Yeah this was me. It was almost like the engine was in fault mode, get to 40mph then die. Would need to do a complete train reboot to get it firing again. Had to abandon it at Slough, which appeared to clear the fault for the AI driver.