I was chatting with an engineering friend the other day, and he asked how the various model railroad scales developed. Apparently, the proportions we use are not standard engineering scales, so how did we end up with 1:48, 1:87, 1:160, etc.? The only explanation I could offer was that a particular dimension, e.g., track guage, was determined first, and then the scale worked out around that. Am I close, or were other factors involved?
Originally the “proportions” of models was largely irrelevant and size was only approximated from the track gauge. The sizes/track spacings were classified as #1, #2, etc “Gauge”. Smaller “Zero” gauge was eventually introduced, which in time became distorted to “O” in the nomenclature. “Scales” were eventually derived from the approximate track guages. The same was largely true for S, HO, and N.
CNJ831
HO scale stands for “Half-O” and roughly is half of O scale, consequently N scale is about half of HO.
Check these out:
http://en.wikipedia.org/wiki/O_scale
http://en.wikipedia.org/wiki/HO_scale
http://en.wikipedia.org/wiki/N_scale
http://en.wikipedia.org/wiki/S_scale
http://en.wikipedia.org/wiki/G_scale
Cheers!
~METRO
In England “O” scale is 7mm = 1ft. (1/43) which correct scale “O” gauge track.
So “HO” at 3.5mm = 1’ is actually 1/2 English “O” scale. (Note the ratios commonly given 1/43 for English “O” scale and 1/87 “HO” are approximate)
US “O” scale, 1/4" = 1ft which is a scale commonly used by Architects.
It’s likely that the 1/43 porportion was first used by Marklin as stated in the wikipedia article, [:o)]but don’t tell an Englishman that[:o)]
Welcome to the wacky world of model railroading scales.
Originally, the toy train manufacturers made them to whatever gauge size appealed. Some labels were marketing ploys - standard gauge.
Eventually scale modeling got involved wtih O scale at 7mm to the foot. When it was imported into the U.S. where metric hadn’t caught on, the scale was changed to 1/4" to the ft (but the gauge stayed the same - some used 17/64 scale to correct this). From there we got HO for half O at 3.5mm to the foot. However, at the time the electric motors available would not fit into models based on the smaller prototypes in Britain. So they upped the scale from 3.5 mm to 4 mm to the foot and called it OO, but kept the HO gauge…
After an early attempt at OOO (1/144), N was introduced using Nine mm gauge track resulting in a scale of 1/160.
TT (TableTop) was invented by Hal Joyce to have something smaller than HO. He used 1/120 based on the engineering scale of 1/10" to the foot.
S was invented to be smaller than O and larger than HO at the convient 3/16" to the foot.
Somewhere in the process #1 was set at 3/8" to the foot.
G was invented by LGB to use #1 standard gauge track as meter gauge track forcing the scale to 1/22.5. This was shifted in the U.S. to 1/2" to the ft or 1/24. 1/20.3 uses the #1 track as 3 ft gauge track. 1/29 was invented by Aristocraft to have standard gauge rolling stock about the same actual size as the narrow gauge LGB rolling stock.
What a mess. Thank goodness for scale rules.
Enjoy
Paul
The other funny thing is that although the gauges originated in Germany, they all have very reasonable Imperial meaurements, rather than metric. 5/4", 3/4", 5/8".
One not mentioned is HOj (1:80 scale on 16.5mm gauge track.) In this case the track gauge came first, then Japanese modelers tried building over existing American-design mechanisms. Since the prototype gauge (in those pre - Bullet Train days) was 42 inches, it turned out that a purely arbitrary scale of 1:80 provided an adequate match.
In 1:80 scale standard 63 inch HO drivers are exactly correct for a JNR D50 class 2-8-0, and the standard 36 inch diameter HO passenger car wheel comes out within a scale millimeter of the standard JNR freight car wheel. Only the track gauge (which should be 13.34mm) is less than wonderful.
Chuck (who models in HOj and occasionally runs US HO scale)
Thanks for the replies, everyone. Looks like my original hunch was at least close. Interesting that the one scale (TT) that seems to have been rationally planned from the ground up to a standard engineering scale, has gone absolutely nowhere (OK, now waiting to be flamed by all the TT-ers out there), while the scales which developed at least somewhat arbitrarily or haphazardly have flourished (after some trial and error). Must be a lesson there somewhere!
Thanks again.
Check this site http://www.ttscale.com/ for what’s available. This scale has lingered on (was/is popular in Eastern Europe) probably because it fits nicely in between HO and N. In many ways it is the perfect scale for the proverbial 4x8 sheet of plywood using 12 - 19 1/2 " curves suitable for all but the largest locomotives and longest (80’) cars.
Enjoy
Paul
I’ve felt that the problem with TT scale (and S scale) was that to offer a reason to switch, the reduction had to be close to 50%. TT and S were only giving about a 76% change.
American TT got sideswiped by two developments - Plastic in HO and then N. TT was still a craftsman’s scale when this happened.
And he returned to the thread suitably chastened . . . . For a scale that’s “gone absolutely nowhere”, there’s some pretty impressive model work out there. My hat is off to the folks working in this scale!