Diesel Classification scheme?

[Allen Hazen]

The other day I was watching a CPR switching move at Whyte Avenue and 102 street, Edmonton AB(*), with the switching locomotive (two unit SD40-2) passing about three feet in front of me. Below the number on the (right) cab-side on one unit (the other was pointing the other way: no sublettering on the left side of its cab) it had
DRF30M / SD40-2
So, how does the CPR's classification scheme for diesels work? "DRF30" I assume means a diesel of 3000 hp for road freight service, but what's M? M-for-modification, because it's a Dash-2, came to mind, but then what did CPR class M630 units? Or is it M for the 13th (or 14th) subclass of 3000 hp freighters (plausible if just about every order of C630M, M630, SD40 and SD40-2 had SOME difference in options specified, I suppose).
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(*) For those not familiar with Edmonton, Whyte Avenue (running east-west) is a major shopping/entertainment street in the southern (Strathcona) part of central Edmonton. The CP line coming up from Calgary ends there: the former passenger station (now a nightclub) is about a block south of Whyte Ave. The yard is basically south of that (tracks fanning out from a point not far from the former passenger station), but one track extends about a block north of Whyte Avenue: when switching a long cut of cars, the switching power pulls across the street. ... Big road-freight power (AC4400/ES44AC) makes it up to about the old passenger station before cutting off and going to "rest" a bit to the East; switching power that I've seen in the past few weeks includes SD40-2 and first generation Geeps.

[Ken V]

You pretty well hit it right on the money. The last letter, which should be in lower case, represents the order number for that class. DRF-30m would be SD40-2's 5675-5717. CPR's M630's were also classified as DRF-30. For more information you can refer to the Canadian Classification topic.

[Allen Hazen]

Thanks Ken V!
(CN's initials for manufacturers have always amused me, since many U.S. railroads use "E" for EMD and "G" for General Electric: precisely the reverse of CN's usage!)
Do you know if CPR adopted its scheme a year or two earlier than CN? Some of the earlier-adopted U.S. classifications didn't specify manufacturer. PRR, for one, started with a system that didn't, then switched to a scheme with "A" for Alco (which would correspond to CN's "M" for Montreal: I think that the Schenectady-built RS-11 of CN's U.S. subsidiaries got "M" as a prefix, with a final letter marking the fact that they weren't really MLW RS-18), "B" for Baldwin, "E" for EMD, "F" for Fairbanks Morse (would CN have used "C" for Canadian Locomotive Company for its F-M design diesels?), "G" for General Electric and "L" for Lima.

[ENR3870]

CP's classification system unlike CN's doesn't differentiate between builders. An SD40-2 is the same class as an MLW M630.

Interestingly enough, the CN SD70M-2's don't have any CN classification symbols, they're simply labeled as SD70M-2. Yet the ES44DC's are in the EF-644 class with the Dash 9's.

[Allen Hazen]

Thanks again!
With the small number of active locomotive builders, and most of the units being ordered belonging to a small number of models(*), it may be that somebody at CN just forgot the tradition of assigning class designations. Penn Central used the ex-PRR classification system, but by the time Conrail was formed in 1976, management apparently felt there was no need for one: Conrail just used builder's models.

(*) Though, given the number of companies marketing hybrid and Genset units, that could be changing!

[CN Sparky]

CP's classification system unlike CN's doesn't differentiate between builders. An SD40-2 is the same class as an MLW M630.

Interestingly enough, the CN SD70M-2's don't have any CN classification symbols, they're simply labeled as SD70M-2. Yet the ES44DC's are in the EF-644 class with the Dash 9's.

Some do.. but they're slow coming. They are the GF-643 class, along with the SD 75's. I've seen a few come through. The original 8000-8024 series seem to have the class markings (specifically, GF-643d) more often than the 8800's do (GF-643e), probably to do with the retrofits they've received and having spent time in a shop somewhere..

[Engineer Spike]

The G is for General Moters Diesel Division, not EMD.