road numbers

Are road numbers like serial numbers, meaning are they unique to that particular RR company. Also, when models are made for railroading, are the road numbers real or do they just put any old number on the scale models?

Each railroad numbers its freight cars as it wishes. The initials identify which railroad (or private car owner) the car belongs to, and the number is unique to the car. On one railroad 123456 may be a boxcar, on another it might be a gondola. There have even been a few very rare instances documented where a painter messed up and there were two of the same number on the same railroad. That was back in the pencil and paper days, with computerization something like that would be found out pronto today.

For the most part I think models these days are accurately numbered although I am not into modeling. Years ago some manufacturers did, and some did not, use correct numbers. When Tyco first made GP20 models in the 1960s, every one, of every different railroad offered, was numbered 5628 (which I think was the number of the demonstrator, but I'm not sure)

Most model manufacturers (the ones that market towards model railroaders, not toy trains) are doing quite a good job of accurately numbering their offerings. There was a time when even the likes of an Athearn would slap any road name on a model, sometimes regardless of whether that road even owned it or not. Nowadays, there's even a lot of instances of the model builders changing details like headlights, etc. for each specific road.

For locomotives (the real ones), they all come from the builders with builders numbers, which are akin to a serial number on any other product, which is selected by the manufacturer. That's how one specific unit could be tracked, as the road number will change anytime the railroad sells the unit...

I've always found it interesting to note cars with "rounded off" road numbers, e.g., yesterday at LaSalle, Colo., were both GATX1000 and MILW100000.

I was working int the yard one day about a year ago and was switching a cut of cars and found the prized UTLX #1.

Sometimes a road number can tell you how many axles and how much horsepower a locomotive has. For example 43600. Sometimes a railroad will put letters as part of the road number. The Québec Central Railway does this.
http://www.railpictures.net/viewphoto.php?id=135398
http://www.railpictures.net/viewphoto.php?id=91414

I don't know where you'll find a locomotive numbered 43600, unless it's Mexico or some industrial operation. US railroads don't exceed 4 digits for locos generally speaking. I believe this is computer-related. For instance UP was running out of number series, and rather than go to 5-digit locos they created "UPY" for yard locomotives.

I have seen pictures in Trains of 2 units of recently merged railroads. Both units had the same number. I work for the D&H. We are owned by CPR. There are some conflicts in numbers here. One example is the Soo SD60s. They are in the 6000 series. So is a class of CP SD40-2s. We have to be sure to use the unit's initials AND number. The same may be true with foreign power. It may have the same number as one of our units. We often get CN SD70 or 75 Ms. Some are in the 5600 series, just like CPR's Sd40-2s.

Another way some railroad numbering systems can confuse you is that for a certain number series all of the evens will be one kind of locomotive, or freight car, while the odds will be something completely different. This once was very common but is rather rare now.

A further confusion factor was on some railroads that had electrifications, like the New Haven. A locomotive with the number 360 would be a steamer, and at the same time there would be a 0360 which would be an electric.