Scale of track

You may be confusing "scale" and "gauge".

Scale is the proportion of the model to the prototype.  If you were talking about the rails themselves, it would be the height and width of the model rail as compared to a prototype rail of a given size (prototype rail is made in various sizes/weights).

Gauge (as it relates to track) is simply the distance measured between railheads.  For U.S. prototype track on most railroads, that measure is four feet, eight-and-a-half inches.

Guess I worded that wrong Allan. If I was to build a U.S.train scale model that fit on our O scale track and scaled it to the track what scale would it be. I know it won't be 1/48 because that is to narrow (proto 48). To put it another way what is the gauge of proto 48 track?

Clem

Perhaps this link to a Proto48 publication will help.

Well where getting closer, I think what I need is someone better at math than myself, which is just about anybody.

I'll take a stab at it:

1.25 inches times X = 4 foot 8.5 inches

1.25X = 56.5

X = 45.2

1:45.2 scale.  Nothing like a nice clear round number. 

I never knew that.  But apparently its 1:87 in Europe though.  Must be an exchange rate thing.  

Engineer humor, Jeff?

Thank you     Now the question is where did 1/45.2 scale come from? This start before Lionel? Is this a metric conversion? How did our O gauge get a 5 foot gauge?

1:87.1 I don't have a clue  

I really shouldn't stay in the house so long

Clem

Well you can build your own track.  But then maybe you will find your hobby isn't running trains any longer just building track, measuring track.  

Clem,

IIRC, the track gauge came first, then pioneer model railroaders had to figure out what scale to use.  In the 1930s and '40s, many modelers used 17/64" = 1' scale.  This works out to 1:45.176.

However, working in this scale must be a pain, so 1:48 or 1/4" scale was a compromise that was much easier to deal with.

Incidentally, in P:48, the minimum track gauge is 1.177" and the maximum is 1.203".  See NMRA Standard S.3.1.

ChipR

Maybe it was from the Russian 5'-0" gauge.

Ya know, the difference between 5'-0" and 4'-8-1/2" is only .073" (a bit more than 1/16" = .0625") in 1/48 scale.  If they held all the other dimensions as close we probably wouldn't have some of the discussions we have.

Perspective (kinda like Bob2s "Opinion" )

The slide ruler sent a man to the moon and back.

I don't get it.  

that's putting the cart before the horse.

"I'm pretty sure that Lionel Cowen came up with the 45.2 number specifically to make sure that there would be no standardization in this hobby, that people would fight and argue and design incompatible control systems and insult each others trains."

No, Mike Wolf invented it, then sued Cowen for using it. It's all discussed and explained in Al Gore's epic autobiography "How Joshua Cowen and I invented the internet so train hobbyists could have a place to chat about how I invented toy trains."

I suspect the track gauge was arbitrary at first, and scale was nebulous.  Quite a bit of older O Scale was done in 17/64, although for most the conversion was simply too tough, when compared to 1/4" scale.

For the vast majority, the difference is not at all noticeable.  I personally notice it, and build most of my locomotives to the larger scale.  I also have a very small collection of 1 1/8" gauge trains.  With the wider tread of O Scale, the sideframes wind up where they should be.

Everybody gets to decide for themselves what to put up with.  Josey cannot stand to be missing a data plate.  I have a difficult time with U shaped boilers.  Some cannot live without cab chatter. Others come unglued when the lettering is not perfect.  It is a hobby, not a science.

The correct expression for true O scale ratios is 7mm to 1 foot.

I have been known to make arithmetic errors.  That said, I get, for 1 1/4" gauge, assuming the prototype is 4'8 1/2" gauge, .2613" per foot. (6.637 mm)

17/64 scale is .265625" per foot (6.7469mm)

7 mm, while larger than either of those, would look best with our wider treads and side frames.  I seriously doubt that any manufacturer will consider any of those scales.

That's a good thing for me, and a bad thing for whoever inherits my collection.  My 17/64 models have a certain uniqueness that a 700E will never have.  Nobody will want them because they do not really match anything else.  On the other hand I pull 1/4" scale cars with them and nobody notices until I tell them.

Some early manufacturers would enlarge certain things so that main and side rods would fit.  You may note that MTH covers that with off- center piston rods and crosshead guides.  There has always been artistic license in our hobby.

No,  7mm/1 ft = 43.5.  It is not an accurate measurement, but simply 2 x 3.5 mm/ft [ = HO ], or, in French logic [ actually, French illogic is more correct ] , " If HO is 1/87, then 0 is 2/87 ".

If 7mm were correct, there would be no need for "Scaleseven" in Britain, which runs 43.5 scale equipment on 33 mm [ not 32 mm ] gauge track.

Given a 32 mm track gauge, 1/45 is the "correct " scale.

Best, SZ

It gets even more interesting. Not all "standard gauge" railroads in the USA use 4'-8 1/2" everywhere. There is a gauge difference in Grand Central Terminal. I can't locate the source, but seem to remember that at least a few tracks are gauged to 4'-10". And I also recall that PRR, at least at one time, used 4'-8" gauge on tangents. (I would have trouble locating this reference also....) Many railroads use various "gauge widening" in certain applications.

Because of this, I have a difficult time understanding why anyone would want to model in P48 or 17/64, especially considering the great difference in the models available compared with 1/48 standard "O". I guess those who model in P48 must have higher "standards" than I.....to me it isn't worth it.

Aren't you sorry you asked?

Well Im with Bob I like 17/64 scale, 1/45 or 6.75mm to the foot, I only have two loco's to this scale but they are some of my favourites. It's to bad early modellers didn't discover the ease of using the metric system. The difference in size, well you wouldn't know, but they do have a presence that sets them apart,but its subtle.      Stephen     (cTr...Choose the Right)

Nope - it is subtle for all but the very largest.  For an 0-6-0 you do not notice it unless you park side by side with an identical 1/4" scale model of the same thing.  My first was an MM-2 - a relatively small Mallet.  Parking it next to a 1/4"scale AC-8, it still looks like a teakettle.

i never measured it, but I bet the Lionel B6 switcher is larger than 1/4" scale.

My Little Engines Pacific is now 1.6" scale.

by the way, the #1 or G gauge folks got it all totally screwed up.  I have no idea what scale fits their gauge.  I have started a 1:29 Harriman Switcher, but ran out of gas machining side rods.