HOW TO WORK WITH HYDROCAL AND OTHER MODELING TIPS 
AN INTRODUCTION TO MODEL RAILROAD SCALES
Most model railroaders know this stuff, but I get a lot of emails from
nonmodel railroaders. So rather than ignoring their questions or taking the
time and effort to explain it over and over I decided to post a web page. And
if you are a model railroader and I have directed you here SHAME ON YOU! You've
asked me a question like how big is something (a model) in real life. Sorry, but
it irrates me that you either don't have a scale ruler or the knowledge to
convert the scale size to real life.
Where to begin? Soon after the first steam locomotive was invented no doubt
some little kid was dragging around a board on a string imagining it was a locomotive
and he was the engineer. We've come a long way since then and the little kids have
grown up. It's now a mature hobby enjoyed by many adults. Early on they were
just toys, in all shapes, and all sizes. Not much attention was paid to scale or
accuracy. Eventually, certain toys caught on. Lionel's early standard gauge, then
the O27. American Flyer stood their ground with something in the middle, 1/64th
scale, which became known as Sscale. Lionel's Oscale wasn't exactly to scale
with the locomotives and cars slightly smaller than the track's width would
indicate. True Oscale is 1/48th scale. And the most popular HO scale 1/87th
came out of Europe was derived from the odd mix of 3.5mm = 1 foot! Why didn't they
choose something simple like 1/8" = 1 foot (1:96th)? It's all very confusing.
No matter why or how here we are with a handful of scales. Besides those in
model railroading there are a bunch in other hobbies such as scale airplanes,
model racecars, military models, war games, voodoo and doll houses. Please don't
ask me questions about those. I don't know. I can only support the few I do. If
something I have works for you that's great, I'm glad to share. But please don't
ask me to figure it out for you or engineer YOUR project. I've got my hands full
with the train stuff. But here are a few clues.
Here's a link to:
The National Model Railroad Association
They are sort of the traffic cops in all this, setting standards, and having fun.
HO SCALE FOOT TO INCH TRICK
Remember this number: 7.25. HO scale is 1/87th scale. So let's divide 87 by 12
which equals 7.25. So if we know let's say a box car is 40 ft. long we divide that
by 7.25 to get roughly 51/2 inches. Yep, a 40 ft. HO scale boxcar is about that.
And if we have a model that is 8 inches long we can multiply it by 7.25 and learn
that it is a scale 58 ft.
I'll let you figure out what the magic number is for your scale.
Oh, I'll give you a clue if you are modeling On30. It is the same as O scale.
Quarter inch anyway... Oh, forget it.
METRIC CONVERSIONS
A European customer asked what are the metric equivalents to our scale feet?
Heck if I know? But let's figure it out.
N scale is tiny. I don't even know what = 1 foot. It is 1:160 so 0.075" = a foot?
Boy, I only do a few things in Nscale. Sorry, it's just not my thing.
And Z scale, forget about it! 1:220 or something like that.
When I was a kid my father brought me a tiny locomotive from Europe (British I
think?). It was TT scale. Later on, well, I was still a kid, someone else gave me
some additional pieces when they learned I was a model railroader. TT is something
like halfHO scale. Sorry, I don't know exactly what. It's not supported in the US.
I doubt it is truly halfHO but a little bit bigger or smaller. Similar is size
Nscale won out.
HO scale by far is the most popular model railroad scale is the US. It was a
popular scale in Europe. In 1959 or so I received my first model train set, an HO
scale Lionel Santa Fe passenger set, for Christmas. I was one happy boy!
Here nearly 50 years later I'm still at it.
HO scale is 3.5mm = foot. 1:87 So that's 12 divided by 87 = 0.1379" = 3.5mm
S scale is 3/16" = foot. 1:64 So 0.1875 = 4.7625mm
O scale is 1/4" = foot. 1:48 So 0.25" = 6.35mm
As I mentioned Lionel "Oscale" is a little smaller, 1:43 or is it 1:32?
Something like that? Standard gauge? O27?? Sorry, I get confused. If it's not true
1/4" I don't really support it other than if it is close. If it works for you, great.
If not, sorry. But you'll have to decide. Don't ask me. I didn't come up with these
crazy scales or loose interpretations thereof.
G scale is another odd one with a bunch of nearby incarnations. There's
true G scale 1:22.5 (one of those European conversions), 1/2" = 1 foot ( I think
call that F scale), and others larger (1:20.3) and smaller (1:29). These all fit
the category of "largescale". I've got a handful of stuff that I generically call
Gscale. It's just BIG stuff roughly double my O scale products. If you need something
more exact to a particular scale you probably don't want my stuff. I just can't do
everything for everyone. I can barely do HO scale for me!
To see how many scale inches something is divide by 12 (12 inches per foot)
times however many inches you need to know, for instance 8 scale inches in O
scale is 6.35mm /12 x 8 = 4.23mm.
So 36" in O scale is 19.05mm and 14.29mm in S.
This site should help with the conversions:
worldwidemetric.com
CONVERTING ONE SCALE TO ANOTHER
Most of my stuff is HO scale (unless otherwise noted) which is a ratio of 1:87. Sscale is 1:64.
So we divide 64 by 87 to get 73.6 percent. HO scale is 73.6% the size of Sscale.
So if something in HO scale is 10 feet it would be 7.36 feet in Sscale.
If you want to know how many real inches that is divide it by the scale (87) = 0.115 feet.
Multiply that x 12 to get 1.379 inches.
So ten feet in HO scale is a little over 7 ft. in S, and about 13/8 real inches.
I know, it's confusing as all heck. Get yourself a good scale ruler if not three or four.
IF SOMETHING IS IN HO SCALE
 for N scale reduce to 54.5% of original
 for S scale enlarge to 135.7%
 for O scale enlarge to 181% of original
CCC
C. C. CROW 's HOW TO CLINICS



