Canadian Pacific Railway compound Mallet steam locomotive no. 5752 and engine crew. The locomotive is one of six 0-6-6-0s built by the road's Angus Shops in Montreal in 1909 for pusher service over the Canadian Rockies on the 2.2% grade out of Field, British Columbia. Note the unusual design of mounting all four cylinders in the middle of the locomotive. While the design was at least somewhat successful, the Canadian Pacific decided to use only rigid-wheelbase locomotives and converted all six 0-6-6-0s to 2-10-0s in 1916-1917, which operated well into the 1950s. These were the only known articulated locomotives ever operated by a Canadian railroad, even though the articulated design was popular among many American roads.