The C-41's also have an interesting history, that is parallel to the K-27's.
They were delivered as Vauclain compounds, like the K-27's.
Also like the K-27's, they were converted to saturated simple engines.
Most of the K-27's and probably all of the C-41's were then converted to superheated engines with piston valves. The K-27's had walschaerts valve gear but the C-41's all stayed with stephenson gear.
There they part company, in that 10 of the C-41's were converted to the narrow gauge K-37's, but only two of the K-27's were ever converted to standard gauge in Mexico, but they stayed as 2-8-2's.