Sharp curves and steep gradients often seem to go together and that was particularly the case where the Wuyiling branch climbed out of Nancha. Just at the point where trains would have liked to build up a bit of momentum for the climb ahead, they had to negotiate a sharp reverse curve at restricted speed.
QJ 2802 had just opened up as the gradient started to bite and QJ 1987 would soon start shoving to keep the train moving around the curves towards the summit. The working was 573/572, the 04:08 Jiamusi - Yichun passenger, on 26 February 1989.