Meaning of Locomotive Numbers

[modelrailroadrookie]

I was just wondering what the 3 digits associated with locomotives mean (for example, 4-4-2. I just made this one up to give you an idea of what I'm talking about.

Please forgive me if this is obvious. I'm a newbie.

[richG]

Here is how you sometimes can find answers on the 'Net also. This will provide a lot of reading.
The numbers are the Whyte system for locomotive wheels.

http://www.google.com/search?hl=en&q=steam+locomotive+wheels&btnG=Search

Rich

[Paul M.]

oo000o
( 4-6-2)

o00000oo
(2-10-4)

etc.

[az2rail]

Did you figure it out from RichG's link? If not, the numbers represent the wheel arrangement of the steam engine. 4-4-2. The first 4 is the number of pilot wheels - those  behind the front pilot. The second 4 is the number of drive wheels - the large ones that accualy move the engine. And the 2 is for the last set of wheels under the cab. This is the total number of wheels of the engine, and does not include the tender. Loooking at the side, the engine would look like a 2-2-1. Hope that helps.

Bruce

[GlennW]

The numbers for steamers do have meaning:
1) Number of pilot wheels, from 0,2,4,6
0 will be for slow service, usually switching
2 will be for freight
4 will be for passenger, as the truck guides the loco along the rail
2) Number of drivers, 2-4-6-8-10-12
power to move the train
3) Number of trailing wheels,, from 0,2,4,6
the larger the number, the bigger the firebox used to make steam!

[Dr EMD]

Ah
The French have to be different

A pacific (4-6-2) is a 2-3-1 under the French system.

Dr EMD
(check my ISP to guess where I'm at)

[rogertra]

Ah
The French have to be different

A pacific (4-6-2) is a 2-3-1 under the French system.

Dr EMD
(check my ISP to guess where I'm at)

It's not the "French" system, it's the European system.

[Cascade Northern]

Here, for an American (oo-OO) type locomotive (the same type as the famous GENERAL from the Civil War).

Whyte Classification -
4-4-0

French UIC -
2'-B

European Classification -
2-2-0

My site has a long list of locomotive classifications - http://hyaklocoworks.weebly.com/locomotive-classification.html

[modelrailroadrookie]

Aha, now I get it! Thanks a lot for the explanations.

[SteamGene]

While a 2-X-X is normally freight and a 4-X-X is normally a passenger engine, this is not totally correct.  The 4-4-0,  2-6-0, 2-6-2, 4-8-2 and 4-8-4 were all dual service locos, though some railroads used them only for freight or only for passenger service.  Then there are the articulated locos, which are X-X-X-X, with the middle two numbers both representing drivers powered by separate cylinders.  Examples are 2-6-6-2 and 2-8-8-2. 
In addition, most wheel arrangements had a name or name.  The 4-4-0 is the American or American Standard, the 2-8-2 is the Mikado while the 4-6-2 is the Pacific.  It's not necessary to say 2-8-0 Consolidation as they mean the same thing.  Some arrangements had several names; the one with the most is probably the 4-8-4, originally called a "Northern," which didn't set well in the South.  There the 4-8-4 was a Dixie or a Greenbriar, or several other names. 
Gene

[jsmvmd]

Dear Gene,

Wasn't the Berk considered to be dual service, too?

Apologies if I was supposed to call it something different, i.e. Mohawk or Kanawha!   

Best Wishes,

Jack

[scottychaos]

Dear Gene,

Wasn't the Berk considered to be dual service, too?

not really..maybe a few were used in passenger service on occasion,
but the vast majority were freight engines..

the 4-8-4 was much more "dual service" than the Berkshire..

Scot

[SteamGene]

Jack,
Everybody but the C&O called it a Berkshire.  I think the Mohawk was the NYC 4-8-2 - the "Water Level Route" surely couldn't have a Mountain!  C&O did use some of their Kanawhas  for passenger service during WWII, but it was a war emergency type thing and not standard practice. 
Gene

[ebtnut]

Well, the name Bershire came from the Berkshire Hills in western Massachusetts, where the prototype Lima 2-8-4 ran on the old Boston and Albany in 1925.  The B&A was controlled by the NYC at that tiime, but was fairly independent in its operations back then.  Those early Berks only had 63" drivers, so were really "super" Mikes.  When the designers realized that the steaming capacity and potential horsepowered weren't being fully utilized, they went back and increased the driver size to 69", thereby allowing both power and speed.  The C&O used their Kanawhas in occasional passenger service, mostly during WWII for troop trains.  I agree that in general the Berks were normally freight locos.  Note also that a large number of these locos were built to the "Van Sweringen" design when those two Cleveland brothers managed to gain control of the Nickle Plate, C&O, Pere Marquette, Erie and maybe one or two other roads.  Details such as dome size and location, applicances and so forth may have differed, but they were fundamentally the same loco.