And in a slightly related note LMS 6201 "Princess Elizabeth" suffered from severely low adhesion in the North West having got stuck in the Blackburn area whilst they resolved the issue (apparently assistance entailed treating the track) and it got moving 88 minutes late (having also had to have its booked water stop). Then for a still unknown reason actually stopped at Wigan North Western, a bonus beyond words for us (especially myself since she stopped perfectly in frame)...
When she departed there was a brief slip of the wheels but that was to be expected as it was below freezing and we had just encountered a strong rain shower.
Video at Wigan if anyone's interested
On the subject of slippery rails a guard I'm friends with mentioned the 150s & 156s he had been working that day seemed to be suffering from wheelslips most of the day. Though to be fair the temperature had been loitering around the zero mark all day, add a drop of rain and bingo - fast frozen rails...
Phil