US Locomotive Class Naming

[TrainzBrainz23]

How do US railroads come up with the class naming of locomotives, like the PRR’s K4 or the SOU Ps-4?

 

[BR60103]

The PRR used wheel arrangements with a number to designate variations or new orders. Since G was a 4-6-0, the 4-6-0-0-6-4 electric locomotive was a GG1.

 

I think other railroads used a similar system, but different letters.

 

Edited March 5, 2020 by BR60103

[pH]

Here's the explanation of the PRR's locomotive classification:

 

https://en.wikipedia.org/wiki/Pennsylvania_Railroad_locomotive_classification

[sncf231e]

The US railroads did not share the same method of class naming for locomotives. Of course the Whyte notation (https://en.wikipedia.org/wiki/Whyte_notation) was used for wheel arrangements. Classification for steam locomotives for all US railroads can be found in the book Guide to North American Steam locomotives published by Kalmbach.

Regards

Fred

[TrainzBrainz23]

3 hours ago, sncf231e said:

The US railroads did not share the same method of class naming for locomotives. Of course the Whyte notation (https://en.wikipedia.org/wiki/Whyte_notation) was used for wheel arrangements. Classification for steam locomotives for all US railroads can be found in the book Guide to North American Steam locomotives published by Kalmbach.

Regards

Fred

Thank you, I will have to check out this book!

[Zunnan]

To muddy the waters, lots of roads assigned different classes of steam locomotive according to their own administrative requirements, but a good number used different formats of a similar system. This being pretty much the same approach a lot of UK pre-grouping and Big Four railways also took where the class or wheel arrangement was assigned a letter, and subsequent letters or numbers denoted the differing design or sub class. In simplest terms think of the LNERs Gresley A1 through to the A4, very similar applies to a good number of US railroads. The Union Pacifics FEF (for Four Eight Four) series of locomotives for example being the FEF-1, FEF-2 and FEF-3 while the nickname for 4-8-4 was often to call them Northerns, and the NYC also named a series of this wheel arrangement Niagras with classifications S-1a, S-1b and S-2.

 

In simplest terms though, an ALCO built 4-8-4 sold to several different roads could have as many different classifications as railroads bought the product for what was essentially the same locomotive (with alterations, modifications and developments to suit each roads specific needs of course...I'm in no way insinuating that an FEF-3 is the same as an S-2, although they do share a development lineage).

 

Diesel classifications are so much simpler, most coming from the manufacturer with the nicknames more often than not coming from the foamers!

[Talltim]

28 minutes ago, Zunnan said:

Diesel classifications are so much simpler, most coming from the manufacturer with the nicknames more often than not coming from the foamers!

Although not always, especially in the earlier days of diesels, when some RRs had their own classifications, e.g. the PRR http://www.contrib.andrew.cmu.edu/~shadow/prr-diesels/diesel-classes.html

[mdvle]

I believe CN and VIA both still maintain their classification systems (VIA inheriting the CN system), and CP might.

 

CN / VIA diesel classifications

 

CP steam and diesel classifications

 

These can typically be seen in small lettering on the sides of the cab.

Edited March 5, 2020 by mdvle

[dckuk]

On 05/03/2020 at 03:02, TrainzBrainz23 said:

How do US railroads come up with the class naming of locomotives, like the PRR’s K4 or the SOU Ps-4?

 

Often these would follow a pattern; a particular wheel arrangement would have a letter designation (or series) such as the “K” for a Pacific, and major version changes would progress the number. Minor changes to a series (such as converting fuels from coal to oil, or adding a particular type of feed water heater) might bring a “subclass”.

 

best bet is to research the particular railroad and see what you can learn...

[Chris M]

I think the 2-8-8-8-2 was given the classification of flippin disaster!

 

Photo

Edited March 6, 2020 by Chris M

[SD45T-2]

Espee used the wheel arrangement as the basis for MOST of its steam classes:

M - Mogul (2-6-0);

Mk - Mikado (2-8-2);

C - Consolidation (2-8-0);

T - Ten-wheeler (4-6-0);

A - Atlantic (4-4-2);

P - Pacific (4-6-2);

E - American (4-4-0);

D - Decapod (2-10);

F - 2-10-2, referred to by most as the "Santa Fe-type" but Espee would not countenance anything of that outfit on THEIR railroad, and I won't either;

S - a catch-all for switchers (0-6-0 and 0-8-0);

MT - Mountain (4-8-2);

AM - Articulated Mogul (2-6-6-2);

AC - Acticulated Consolidation (4-8-8-2 and 2-8-8-4). The Cab-forwards were Classes AC1-8 and AC10-12 while the AC-9s were conventionally laid out.

GS - Northern (4-8-4), with GS standing for either Golden State or, between 1941 and 1945 to get them built, General Service;

SP - Southern Pacific (4-10-2).

 

Diesels were latterly identified by manufacturer - A for ALCo, E for EMD, K for Krauss-Maffei, G for GE -number of axles, and 100s of BHP with a suffix letter for Cotton Belt classes or rebuilds/refinancing and suffix number for production groups: EF636C-3 was an EMD Freight loco, with 6 axles, 3600BHP, on a Cotton Belt order, being the third group of EF636s.

 

Cotton Belt steam loco classes were determined by cylinder dimensions; DRGW steam by wheel arrangement and tractive effort in 1000s of pounds, though both Mountains and Northerns were class "M" locos.

 

The basic rule is, as stated above in this thread - read up on your chosen railroad's practice.

 

[cooley_boy]

Worth noting here that most answers so far are for steam locomotives. In regards to diesel locomotive power the class types are determind by the manufactures. Though the railroads may change it to suit their own classification. So you will get cases where the same locomotive will have several different classification depending on the railroad. 

For example:

GE built "Gevo" units classed as ES44AC are classed as C45ACCTEs with the Union Pacific.