How much bigger is O versus HO in inches, and is their a formula for this?
HO scale is 1/87th life size. O scale is 1/48th life size. Multiply HO scale by 1.8125 to get O scale size or multiply O scale by 0.5517 to get HO scale size.
In O gauge one inch equals 48 inches, in HO one inch = 87 inches. So O gauge is almost twice as big as HO.
The ratio is 87/48 for converting HO to O.
Keep in mind that this is a linear dimension. As noted above this is 1.8125. This is useful for comparing curves and train length.
For a layout use an area dimension which is 1.8125 squared. Or 3.285. This means an O layout is 3.285 times larger than the same layout in HO.
The models themselves are three dimensional which is 1.8125 cubed. Or 5.954. This means an O scale engine is almost 6 times larger than the same HO engine.
Enjoy
Paul
The origin of HO is “half O Gauge”. As others have stated not completely accurate but close.
That’s hitting the old “Kiss Principal” square on the head! Thanks for the short-simple answer NDBPRR!
6 times larger is a confusion of scale, to say the least! In all my years in hobbies using scale as a means of determining size I’ve never expressed scale by volume and would never consider doing so.
If HO where truly 1/2 O scale it would be to a scale of 96 and not 87.
The correct proportion for O scale is 7mm = 1 foot, or 1:43.5 scale. Half of that is 3.5mm = 1 foot, or 1:87 scale - the measurements for HO scale.
In the US when O scale arrived from Europe, few people here knew how to use metric measurements, so we began using a scale of 1/4" = 1 foot. That scale is 1:48. It also means in North America, O model trains are undersized slightly, and O gauge track (1-1/4") works out to be five feet, instead of the correct 4’ 8-1/2".
Comparing HO to O , in my experience O is about 2 times…as expensive [;)]
Its a little more complicated. Originally gauges were numbered and O (or “ought” as in zero) guage was 1 1/4" with 1/4" scale superstructures. That ends up with 1/4" scale models on 5 ft gauge. At some point somebody decided that they wanted a more scale appearance so, keeping the guage (and wheelsets and mechanisms) the same they changed the scale of the superstructure so the gauge would be closer to 4’8 1/2". They chose 7mm, 1:43.5 scale. In 7mm scale 1.25" gauge scales out to 4’6 1/2". Closer to standard gauge.
Since 7mm modelers were the “scale” modelers, when they decided on the size of smaller “scale " models, they chose 3.5 mm or 1/87 scale, one half of the 7mm scale and made guage closer to 4’ 81/2”.
Somehow, I think the OP got his question answered…
To oversimplify with word pictures…
|||| = O Scale
|| = HO Scale
| = N Scale
It’s true though. A cubic yard is nine times the size of a cubic foot, despite a foot being one third of a yard.
Volume scale comes into play when models are going to be used in a wind tunnel or test tank. Neither has much applicability to model trains.
Chuck (Modeling Central Japan in September, 1964 - 4.0 in Naval Architecture 1957)
Just for fun…
You can build a O-27 layout on a 36" x 80" hollow core door.[:O]
Depends on what you’re trying to visualize. Since US O scale is roughly twice HO in every dimension, a given model has about 8 times the volume of its HO counterpart (2 cubed). Many a newcomer to O has been surprised at what the sheer size of the models means for planning and otherwise thinking in three dimensions. It’s an important component of the learning curve involved when switching scales.
No … a cubic yard is 27 cubic feet … 3x3x3. The nine is area (square feet) …3x3
Giving thought to NP’s comment, though, our scales are NOT volumes, but proportions. Our models are 1/xxth the size of the real ones. Is that to say 87 of my HO scale boxcars will haul as much as one real boxcar? Of course not! You’d have to have 87x87x87 (658,503) of them. At ten bucks a piece, I think one real boxcar would be cheaper. None of us go around saying “I model in 1/658,000ths volume scale”, but it would be fairly common to hear “I model in 1/24th scale” (especially for “odd” scales).
Brad
Deleted.
The OP has three threads started with vague variations of this question. If you tell us why you are asking, and what you are trying to do, someone might help you.
He got all the help he needed on the first page of this thread and I did not find his question to be vague.
It’s really none of my business,but the OP,has started,19 thread’s and has only replied,to one of them…
Cheers,
Frank