The S-1 was the standard freight locomotive of all Canadian National predecessors from 1913 onwards. It was a Mikado with 63-inch drivers and 27 by 30-inch cylinders. The subclasses S-1-a to e were used by the Canadian Government Railways and were only built by Canadian manufacturers. The Grand Trunk operated classes S-1-f to h, which also came from US manufacturers. After these batches were built until 1918, it was not until 1926 that the CN had two more S-1-j built. Three locomotives were preserved, of which only 3254 was operational until 2012. The 3377 had before been dismantled to provide spare parts for 3254.