There is no hard and fast rule. There is stuff that was sold as O27 that is built to scale. There is stuff that was sold as O (now often called "O31") that is not built to scale. There is only the generalization that O tends to be closer to scale and more expensive than O27.
The diameters of traditional tubular track are measured to the outside ends of the ties, not to the center of the track. Thus the actual diameter of O27 is 25 inches, because of the 2-inch ties, and the radius 12.5 inches. O ties are 2.25 inches long; and the actual radius is 14.142 inches; so its really about O30.5 (and is in fact sometimes called O30).
O27 type track can be found not just in the 27-inch diameter but also O34 (old Marx) and O42, O54, and O72 (K-Line).
My personal obsession is modifying stuff to run on O27 that was not meant to.
Bob Nelson
"O means that it is scale and most often cant run on O-27."
The above statement is not entirely correct. Let's put it this way--any three rail rolling stock listed as scale or "Standard-O" is built to scale dimensions. However, just because something is listed as O doesn't necessarily mean it is scale. As others have said O is typically larger than O27 and may not be able to negotiate a 27" diameter curve.
The best thing to do is ask someone to show you the size differences. It can be confusing until you see them next to each other.
Lionel collector, stuck in an N scaler's modelling space.
Jimkat,
The terms O-27, O-gauge, O-scale, and Standard-O* cover a confusing mare's nest of sizes and designs. The one constant among them is that the distance between the outer rails is always the same, so the wheels will always rest on the track. However, the the rate of curvature of the track, and consequently the locos and cars that can run on them, can vary all over the place, as can the sizes of the locomotives and cars -- within limits. These variations can make for important differences in operation and appearance.
Operationally, the limiting factors revolve around (1) the requirements of the largest locomotive and (2) those of the switches (turnouts). As a general rule: the wider the radius of the curves, the better things look, assuming you have sufficient space in your train room to allow it.
The rate of curvature is customarily described as the diameter of the tightest possible circle of track of a given specification; i.e., 27 inches, 31 inches, 36 inches, 72 inches, etc.
As long as the rate of curvature of the track is large enough, any of the O-gauge family of locos and cars will run on the same layout. The fewest locos/cars will run on the the track with the lowest diameter, 27 inches. Virtually anything will run on track of the greatest diameter, 96 inches or more -- and be and look "comfortable" doing it.
Everything being talked about here is "three-rail," also occasionally referred to as "tinplate" or even "Lionel," even though there are many other quality manufacturers. (There is also two-rail O-gauge, but it is not compatible with three-rail, at least as far as anyone new to the hobby is concerned.)
Within the constraints noted above, you can mix and match at will. The only determining factor is appearance. If you put an O-scale boxcar next to an O-27 boxcar, the O-scale may look out of place (too large) or the O-27 may appear too small. Some folks counteract this by not placing two cars of noticeably different size immediately adjacent to one another but rather separate them with a couple of flatcars, for example, to fool the eye a little.
The fact is that real railroad cars differ greatly in size also. When they're your trains you can do whatever you please. (But see the next paragraph....)
Within this forum, as well as throughout the train-hobby in general, you have an entire range of folks ranging from the admirers of totally unrealistic toys to the guys known as "rivet counters" who won't settle for anything less than exact copies of prototypical stock. You have to decide what you will enjoy in your personal layout, and pick your friends accordingly.
*There are also much larger trains called "Standard Gauge" just to add to the confusion. They are not compatible with the O-gauge "family" of trains.
Welcome jimkat.
It sounds like you have a pretty good collection there already. I ordinarily try to avoid mixing O27 with my more scale sized equipment (exceptions being Lionel's Hi-Cube boxcars and auto racks). The O27 rolling stock tends to look too diminutive. But, since you are thinking two train operation, might I offer the advice of running your O27 equipment towards the back of your layout, or on an upper level (which would facility return loops with O27 curves).
...and the biggest piece of advise that I offer all my friends, is avoid the temptation to buy everything in a bright orange box. Give some careful thought to the type of layout you want to construct. Include accessory placement, or an industry siding, a region, a season, and possibly an era.
Best wishes, and remember the fellas on this forum are a valuable resource.
As far as MTH goes....anything marked "Premier" will probably be scale and noticably larger. Rail King stuff is smaller (unless it is specifically marked scale).
Jim H
Did your set come with Fastrak (built in road base) or is it tubular track? If it is Fastrak, it actually has 036 curves and will work with almost all engines and rolling stock.
The cars may work on 027 but are probably "traditional" sized which is bigger than the smallest cars but smaller than "scale" cars. You will find they look fine with anything that is not "scale" sized. Try taking a car to your local hobby shop and see how they compare. Your cars will work well on any 3 rail track.
There's absolutely nothing wrong with either approach to 3 rail O-Gauge. It really depends on what turns you on. There is only one directive--have fun. Layouts can be toy train, hirail or somewhere in between. It's up to you.
However, in answer to your question, "Can I mix and match or will the size difference be too noticeable?", the answer is the size difference will be noticeable. Scale sized rolling stock will typically be higher, wider and longer than traditionally sized O or O27.
Dave
It's a TOY, A child's PLAYTHING!!! (Woody from Toy Story)
Hi Jimkat,
027 and 0 mix up well as far as the rolling stock goes. Sometimes 027 is a bit smaller (postwar) then modern rolling stock, but as long as you don't mix too different sizes in one train, it's hard to tell the difference. The main difference is in the hight of the tracks. 027 track is about half as high as 0 track end also the rail itself is narrower in size (so the track connecting pins don't fit between 027 an 0 and vice versa)
Also 027 is the size of the smallest curve, which is 27 inch in diameter. The 027 rolling stock will negociate that curve without any problems, but the modern 0 gauge stuff requires 031 (so 31 inch diameter) for the narrowest curve to negotiate.
In the postwar time Lionel used 027 as a mark to tell that it is not truly a scale locomotive, but it's sized down to handle the sharp curves and therefor the size of the engine and rolling stock was somewhat smaller then the scale of 0 gauge would expect them to be.
However, when you start from scratch, it's best to use 031 or 042 size curves as a minimum, because with that you have choise of all kinds of riolling stock, in 027 or scale size.
Both curve diameters are available in 0 and 027 size track..
Our community is FREE to join. To participate you must either login or register for an account.
Get the Classic Toy Trains newsletter delivered to your inbox twice a month