They are well known to the CPR fans, especially in BC.
There were 3 altogether, class S1a-c. They were 50 ton, 3 truck designs. Primary assignments were the steep mineral branches in South West BC. Omar Lavallee’s CP Steam Locomotive book has 2 pictures and a CP line drawing plus more info on them. Both the photos, of 111 and 5903, have cow catcher type pilots on the front. The line drawing shows these pilots at both ends.