“Souya Main Line” connected Asahikawa, located at the centre of Hokkaidou, and Wakikanai, the northest city in Japan. I used to travel to Wakkanai by a night train hauled by JNR C55 class. This area was quite cold and the night train often delayed because of too cold weather. It was so cold that it was hard to get up enough steam in night time.
JNR C55 Class
C55 class was the forerunner of modern JNR locos. They were built from 1935 for second class line passenger services. They were the last passenger model in JNR that had beautiful large 1750mm spoke drivers. Most locos designed after C55 had box drivers. The spoke drivers of C55 class were not simple spoke wheels, but they had web among spokes and outer limb for reinforcement. They say this design was quite successful and webbed spoke drivers were very strong even comparing with box drivers.