Loco Numbering System

I have a new loco for my layout . “On30 Modern 4-4-0 American outside frame loco” (DCC) .. c. 1920’s. I was thinking about weathering it and realized that it needed lettering and numbering before even starting the weathering. That got me to thinking about the number on the cab.

There was a discussion on the Model Railroader forum on this – Locomotive numbering. I’m going to pull out the meat of the series of posts:

  • Locomotives, steam or diesel, are numbered in classes, as example, Santa Fe F units were in 100, 200, 300, etc. classes. GP’s were not numbered in the same classes, they had their own
  • Most locomotive numbering systems are ‘class’ based. For example, a railroad may choose to place all 6 axle engines in the 6000 series. They will put older SD7/9 engines in the 6300 series, SD40-2’s in the 6600 series and SD70ACe engines in the 6700 series.
  • Other railroads may choose a horsepower based system, where SD70ACE’s are in the 4300 series, ES44AC’s are in the 4400 series, GP38’s are in the 2000 series. But for most railroads, locomotives (steam and diesel) came in classes and those classes would have a number. So for example there might a “4000” class consisting of 25 engines: Number 4000, number 4001, number 4002 and so on.
  • Locomotive numbering is purely a management decision and is totally arbitrary depending on what the management goals are trying to do with the numbering system. Sometimes it designates the horsepower, sometimes the series of engine, sometimes the model, sometimes the service, sometimes the order the engines were bought, sometimes whatever number was available.

I rather like the idea of a simple class system based on the number of axles – but that work for steam locomotives? Let’s look at that ..

  • 2000 Series [4 axle] – A 0-4-0 switcher would be in there
  • 3000 Series [6 axle] – 0-4-2T, 0-6-0, 2-4-0 Porter .. again numbers could start for each wheel arrangement as a sub-set of the number of wheels like .. 3000, 3300, 3500
  • 4000 Series [8 axle] – 4-4-0 with it’s 4 axles. There was a 2-4-2 Columbia with something like 8 built between 1877-1878 – which could be accommodated by say starting the numbers at 4300 for the switcher and 4500 for the Columbia.
  • 12000 Series [12 axle] – getting into a 4-8-8-4 Big Boy with it’s 12 axles you would get into 5 digits.

Doable I suppose .. but I have to remind myself that this is all a thought experiment. I have one 4-4-0 that I want to number. Sooo. Without looking too deeply into it I am going to *assume* that the ‘First Generation 4-4-0 locos’ the railroad owned was in the 1860’s. In the 1880’s Second Generation and my own loco in the 1920’s call it Third Generation. Soooo .. let’s virtually number the First Generation locos 4000 series; the Second Generation locos 4200 series and my Third Generation in the 4400 series. If it was the 12th loco in this ‘Third Generation’ then I could number it 4412

Note: Remember I only am wanting to number the ONE locomotive. I just wanted something logical .. not just go and slap on a random number .. and honestly .. I think I was bored when I wrote this up.

I was talking about this with David Mason and he suggested dropping to three digits for a smaller railroad. I had thought about doing just that. First digit would be the class by number of axles, Second digit a sub-class … switcher vrs. road engine perhaps .. or arrangement of wheels.

  • 200 Series – 0-4-0
  • 300 Series – 0-4-2T, 0-6-0, 2-4-0 [Could put the switchers into a class with numbering something like 300 – 339 and the 2-4-0 340 ~]
  • 400 Series – 4-4-0, 2-4-2 [4-4-0 – 400 – 419 and the 2-4-2 420~]
  • 500 Series – 2-8-0, 4-4-2
  • 600 Series – 2-8-2, 4-8-0
  • 700 Series – 2-8-4, 4-8-2
  • 800 Series – 4-8-8-4

With three digits then, my ‘Third Generation’ 4-4-0 for my railroad would with it’s four axles be in the 400 series. Let’s say that the railroad in 1920(ish) still had some 2nd Generation 4-4-0 running. They could be numbered 400-420. My 3rd Generation 4-4-0 would be in the series starting with 421. It is the twelfth engine so it would be numbered 432

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