The strange case of CN 4824

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Posted by daveklepper on Monday, August 9, 2021 4:24 AM

since this particular locomtive was rated only at 1500HP instead of the GP-9's 1750HP, it's a  GP-7 in my book.

Of course it probably had the GP-9's load-regulator control system, which I holped design, EMD summer 1982; but so did B&M GP-7 which I helped test on the B&M winter 1952-1953.

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Posted by Leo_Ames on Wednesday, August 4, 2021 4:08 PM

That happens a lot with similar cases. 

In particular, the F9 model has lots of instances along these lines thanks to several roads having earlier F units rebuilt to F9 standards with little more than the carbody and trucks being recycled.

The most famous example was Union Pacific's fleet of F9's, which some sources (like the Wikipedia article) don't even acknowledge the existence of. Yet to Union Pacific and EMD, they were considered brand new F9's.

Don Strack has a good article up about that at his UtahRails website and I think he even mentions the same thing about railfan abbreviations that have been attached to UP's F9's. Yet to the Union Pacific and EMD, they were always considered F9's since that's exactly what they were in all important respects, albeit in remanufactured F3 carbodies.

A similar and perhaps most well known example along the lines of this Canadian National Geep, were the GP9's that Great Northern accepted which recycled the main generator, trucks, and maybe the traction motors from traded in FT's. These 1350 HP GP9's were known as GP5's during their Burlington Northern era (Unsure if GN differentiated them from a standard GP9). Several remain today on the BNSF roster, rebuilt as GP28's thirty years ago.

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The strange case of CN 4824
Posted by SSW9389 on Wednesday, August 4, 2021 6:38 AM

Six EMD F3s were exported to Canada in May 1948. These were the two ABA sets of order E958 shipped on May 28, 1948 numbered 9000-9005. The booster units were the 9001 and 9004. CN F3A 9005 was wrecked at South Junction, Ontario on May 17, 1958 and was sent to the GMD plant at London, Ontario. 


GMD built a general purpose unit for CN on order #A-1714 that used parts of the wrecked F3A. The unit resembled a phase 3 GP9 like all the other  GP9s built at that time. The unit was shipped in October 1958.  The unit was numbered 4824 to take the roster slot just after the CN's 24 GP7s 4800-4823. 


The strange part of this case is how this unit is classified by diesel historians. You can find it listed as a GP7, GP7M, and GP7R. The GMD production records show it as a GP9.


Ed in Kentucky


COTTON BELT: Runs like a Blue Streak!

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