Indeed interesting. From the 50s to mid 70s, most of Canadian Pacific's FM fleet dominated the former southern mainline between Cranbrook and Spences Bridge. A large new engine shop was built in the 1950s at Nelson to maintain the FM and other first generation units. As a youngster just before the days of the internet, I became fascinated with FM power, looking at pictures in various books of three H24-66 six axle units assigned to the yard in Trail BC, struggling to work short trains of phosphate rock up the 4% grade up to Warfield where a large fertilizer plant was located. This was done with two crews, two units up front and a single unit pushing on the tail with a unique shorty caboose and was done several times a day. Up to 7 GP38s and GP9s would later be used to do the same job and were not nearly efficient as the FM units. This piece of railroad is likely the most dangerous in the Pacific Northwest to operate.
In the late 70s after much planning, CP would launch a major rebuild program for first generation diesels.
https://www.cptracks.ca/images/CPTRACKS ... SAMPLE.pdf outlines this program. What is not mentioned in the program outline and has been mentioned elsewhere in published documents is that there was a earlier proposal to include the FM fleet in the rebuild program as well and was later terminated for unknown reasons. One can only speculate to what rebuilds of the FM units would have looked like, given how extensive CP's rebuild program was at the time (essentially new units) and continued into the early 90s. Many of these rebuilt units are still running for shortlines to this day, a testament to the work done to these units. It would have been neat to have seen the FM units get the same treatment and one could speculate if any would be running to this day as a result.