Works for Me

Every railroad had a different system for car numbering. Yours looks as good as any for a small railroad.

Of course, some smaller companies' "system" consists of keeping whatever original numbers their secondhand equipment had when acquired.

RR Tankcars

Although, most railroads did not own tank cars for revenue service. Tankcars were not really general service cars (even if the design is generic, once used for one product it couldn't really be loaded with anything else without contaminating that load, unless it was cleaned first). Most tank cars were privately owned by the shipper, or leased from a third party like UTLX, etc.

Any railroad-owned tank cars would usually be company-service fuel, oil, water or other work service cars, so they'd naturally be numbered somewhere in with your other MOW cars.

Any actual revenue tank cars on your layout would probably all have private owner reporting marks and numbers.

Why reinvent the wheel

Why not find a prototype that is near what you model and the era you model and follow their numbering system.   

ratled

ORER

You might want to try and find an Official Railway Equipment Register (ORER) a document the size of a phone book that is published quarterly.  It lists the numbers and general physical characteristics of every car in interchange service in N America.  You can find copies for sale on e-Bay, occasional antique stores, railroad book sellers and on CD or DVD from different vendors (Westerfield for one).

That will give you some ideas.

Most railroads are not that neat.  Number series fill up, cars are changed from one series to another as they are rebuilt.  Some roads number series sequentially.  So the first 100 boxcars are numbered 1-100, the next 500 gondolas are numbered 101-600, the next 50 boxcars are 601-650, etc.

If you are talking about a CLASS system that also varies between railroads.  A car might have 3 or 4 "types" on the same railroad.  There would the general AAR type (XM), the AAR mechanical code (B302), railroad mechanical code B70-27 and the operating car type B5A.  All in use by the railroad at the same time.  Some road had a class that was a the car type, followed b the capacity and sequential order.  So the 27th order for 70 ton boxcars would be class B70-27. Some used a letter for the design and a number for the sequence of the design, such as the PRR X29.  Some used 2 letters with a sub letter for the sequence of design, such as the RDG class XMc.  Some operating codes combine letters and numbers to indicate the physical characteristics of the cars.  So a 70 ton plain boxcar with double doors might be a B5D while a 50 ft cushion underframe double door boxcar might be a BED.

Pretty much room for anything you want to do.  And if you come up with a plan and find you have go outside the convention, that's prototypical too.

   I freelance a railroad,

I freelance a railroad, and what you have there should work. As others have mentioned, each railroad has their own system. For instance, my boxcars start 10XX. Flat cars are 30XX. Stock cars are 80XX, and so on. Older cars of course would have lower numbers in a series, Older wood sided box cars have a lower number than a more modern steel sided box car. You are on the right track. That's one thing that's nice about freelancing.

Time

On other consideration I will mention is that model railroaders often don't take into account the progression of time.  If a railroad sets its numbering system in 1965 and then in 1975 the double stack well car comes about, they have to rearrange things to fit a new car type into the series.   The didn't leave a "hole" in the numbering system because there weren't any of those type of cars.  Similarly mergers and aquisitions can influence numbering. 

Your numbering scheme allows for 99 boxcars.  Your railroad owns 55, then buys two smaller roads with 25 each and buys 20 new ones to replace older ones that are wearing out.  Your railroad nominally has to allow numbering spaces for 125 cars.  Granted after all the new cars are delivered, some of the old cars can be retired, but they will probably be piecemeal. 

You allocate 25 numbers for the old boxcars in series 1000-1024, but because of wrecks and retirements there are only 15 cars left in that series. When you buy new boxcars, you probably won't want to mix them in with the old number series, you will want a new number series  to make them more visible.  You will end up with holes and gaps. 

I know personally of situations where because of mergers, engines were in shops being renumbered but because of new locomotive purchases, the engines had to be re-renumbered before they left the shop after the first renumbering.

I personally think that a "messier" numbering system can add to the back story and history of the railroad.  Gons 5001-5025 were the original high side gons, but the 5100-5125 gons were acquired when the PBC&N went bankrupt and the 5226-5235 were 10 gons built to the same design as the 5001 when 10 of them were lost in the great Dry Gulch Bridge Fire of 1914.  The 1065-1079 high side gons were originally boxcars, but they had their roofs removed and doors filled in to become high side wood chip gons.  Cars 5040-5049 are the same design but were built as chip gons to start with. 

Don't be afraid to have fun with it.

Thank you all

for the idea's !

Think I can safely stick to my original idea, a hundred cars of each class will leave some room for changes

The tankers will go to both the Consolidated Narrow Gauge Lines and the chemical plant that is near Clearview (!) on the F&B RR. Do think the RR will own a set or 2 of chemical tankers, an investment that was made after a visit from a Mr. McKinsey ...

cheers, Leo

Oops forgot

yes, it will be messy

cheers, Leo

Messy Numbering

Or to tie things together and carry it farther, let's say those existing 55 cars are numbered 1000-1054, and when that other railroads are acquired through the merger, since those 50 new cars don't fit in the remaining space because there's that series of ventilated boxcars starting at 1100. So the two batches of 25 secondhand cars are renumbered into the 1200-1224 and 1225-1249 series. Then the order of 20 new cars goes into the standard 1000 range as 1055-1074.

Maybe later they acquire some new specially-equipped boxcars with interior bulkheads, parts racks or other special loading features that are assigned to a particular service for a particular customer. To keep these separated from their general service cars, these go in a different number range, let's say 1900-1904. (It's a small customer, so only a few cars are needed.) Another 10 car series of new assigned service boxcars for another customer is later added as 1905-1914. And so on.

So now we have boxcars in at least three separate ranges (1000, 1200, 1900) with additional ventilated boxcars in the 1100 range and reefers in the 1400 series. It's still following a very logical system, even though we have very similar if not identical cars separated by large gaps and groups of other cars types.

Now time marches on, and some of those original 1000-1054 cars get rebuilt or assigned to a particular service and renumbered at random into some additional 1900 blocks, some get rebuilt into woodchip cars or assigned to work service and renumbered with 9000 series numbers. Eventually those remaining woodchip conversions get renumbered to 5050-5057 (maybe through attrition or random conversions there's only eight left at that point) following the other woodchip gondolas, and now the 1000-1049 range is completely empty again for an order of those new-fangled modern 50' boxcars. So now you have plenty of situations where newer cars occupy "earlier" number series compared to older equipment.

Same with the loco's

There are about 70 loco's in the F&B roster, and I spent a nice quiet Sunday arranging their numbers starting with the original loco's and working my way through purchases, wrecks, sales etc, right up to the latest diesels. The chemical plant and the wharf do not own their loco's, leasing them from the F&B is still mandatory if they want to be connected to the system. Up till now that is ...

cheers, Leo

Work Equipment Consideration

Most of my experience with work equipment showed that the RR prefixed all of the MOW series with X or W. X was usually used for cranes and plows, and W for Work equipment such as track gang cars. 

Sometimes for the likes of cranes, they were in their own series; X1, X2, etc.  Whereas work equipment could often be a retired passenger or flat car for example, and then retained its old number, with a W prefixed.  So an old coach # 24 became W24 when in work service.

Regarding a twist in regular revenue car numbers, sometimes the RR numbered a series in all even or all odd numbers.

Thanks Milt !

Indeed, most if not all MOW stock on the F&B is made from ex- regular rolling stock, I used a couple of short cabeese to make a weed killer train and old tender frames are used as well, the ex-tenders will get new MOW numbers though as the old loco numbers could have been given to new loco's.

I have two traveling cranes, so I could (for instance) number the boom carrying flats W1423 and W1408 and the cranes X9003 and X9005 as they would get a new MOW number as well.

Hmmm, even such a simple task as dealing out numbers makes for some nice puzzling It certainly lets you ponder over the history of the line.

I'm not sure if I have mentioned it before, but I'd realy like to be able to set the era on the railroad (more or less) by the rolling stock that is running on the layout, so an old 4-4-0 with low sided gondola's and a diesel or modern 2-8-0 with hoppers. All with a very wide range of acceptance

cheers, Leo

Prefixed numbers

Odd/even numbering

Numbering

Some roads had gons even numbers, boxcars odd numbers, (or something to that effect) in the same general number range.     

If you only have a handful of engines, 2-digit numbers would work, with freight cars on the 4-digit range.  Most railroad-owned freight cars are 5 and 6 digit numbers, leaving 4 digit and smaller numbers for locomotives.  The computer system cannot handle a 5-digit locomotive number, although it was done in Mexico. 

Current Amtrak-compatible private passenger cars are mostly in the PPCX 800xxx number range.