As shown by the screenshot below this train departed Limestreet with a red lamp on the front still. It also seemed to move under some magical power as there was now chuffs or open cylinder drains visible. Not sure why as I had seen this loco back into Limestreet perfectly fine. Also I have never realised how short Xbox draw distance is until I looked out of Limestreet towards the cutting.
The AI locos do not chug at all, it's silent except the wheel clank sounds. Very weird and disappointing as it ruins immersion for free roam. You would think going out of Lime Street you could hear them working hard but no...