Mass is Bigger than scale

[FJ and G]

Just returned from the bookstore (picked up the latest TRP Railroad Press because good big article on the Santa Fe in Arizona).

I leafed thru the various model RR magazines and found a MRC. In it is an O scale (2 rail) layout and history of that RR that goes around Vancouver Island (eskimo or something like that railroad). The article mentions that although O scale is twice as big as HO, it actually is 8 times more massive than HO, making O scale much more substantial, hefty and better able to track well and perform better with electrical pickup.

It's an interesting relationship, where scale is linear and mass is...now help me with the right word: a geometrical increase in size? or logorithmic? or exponential?

As you can see, my physics/math is poor (my daughter's 2 favorite subjects!--I must have a hidden or recessed math gene just waiting to be coaxed out because she's a math genius, barely cracking a book and understanding it all).

Anyway, what I mean to say is that our nice toy trains are so much more massive than the smaller scales--now there, I said it without math and you all can understand.

Course ours look pidly compared w/G or small trains you can ride!

dav

[lionelsoni]

RMC. Esquimalt & Nanaimo. Mass varies as the cube of scale.

The acceleration due to gravity scales linearly; so in O scale it is about 1500 feet/sec2, compared to 32 for us. This is why the slightest rocking motion of a model train looks so unrealistic. If we were to (1) run an O-scale train at about 7 times its correct speed, (2) make a video tape of it, then (3) slow it down by the same ratio, it would look much more realistic. Some operators do at least follow step (1) of this procedure.

[FJ and G]

"Mass varies as the cube of scale"

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Very elegantly put, Bob, and your illustration of speed and the camera is apropos.

Now, perhaps I should have titled this thread: "My trains are bigger than your trains."

But we don't want to get too Freudian here, now do we?

Dave V.

[Anonymous]

Linear distance is linearly related in scale, so 100 feet = 100/48 or a little more than 2 feet when scaled. Volume (& mass) are related by the cube of the scale. So, since O scale is approximately twice the size of HO, the cube of 2 is 8 so the volume & mass of O scale trains are 8 times greater.

In movie special effects, minature shots are always recorded with the film moving through the camera at a greater than normal speed. When it gets played back, everything looks much more realistic for the reasons Bob said.

Does anybody know if the mass of G scale trains also scales up from O scale similarly?

Tony

[3railguy]

It's a simple linear, 3 dimensional equation. Yes, O scale is twice as big as HO. But, masswise, you take length x width x height. In other words 2 x 2 x 2 = 8. It's like comparing the weight of a cubic yard of concrete to a cubic foot. A yard is three feet but there are 27 CUBIC feet in a CUBIC yard (3x3x3=27). O scale is really 1.8125 times bigger than HO (87/48=1.8125) So masswise, it works out to 6 times larger (5.95). There are some exponential equations when it comes to energy used, stopping distance, etc.

[Anonymous]

mass has no scalar factor. If you want something that has half the mass of something else, you cut the mass in half. If you are asking the question of what would a box car weigh if it was 1/48 in size you now have to ask whether the material making up the boxcar are also scaled to 1/48? Even if it was, it would not behave like a 1:1 boxcar would because it isn't operating in 1/48 scale gravity or be made up of 1/48 scale atoms. If I build an exact scale model of an airplane and try to fly it, it will not fly like the real airplane would because it 's opeating in 1:1 air. The chord of the wings and other factors have to be taken into account or the model won't fly.

[3railguy]

chukin,
His source was comparing O scale models to HO models. Nothing about scaling down 1/1 alloys was mentioned in his post.. Since the same zinc alloy can be used to cast an HO model as an O scale model, without scaling down the atoms, the weight per cubic inch is a linear equation. The term 'mass" was being used loosely (like tinplate) because that's what he used in his post because his source said "massive".

[Anonymous]

And then there's me....The Santa Fe is in AZ?? Maybe Flagstaff? I'm in Tucson, and all I see is Union Pacific.

[daan]

If you take of the plastic cap from a h0 GP, all you see under it is engine, weight, flywheels and a bit of space for the headlight, otherwise it would only heat the metal.
If I take off the cap of my lionel GP I see and endless emptyness. Somewhere there stands the E-unit and on the other side is the engine. In the middle there is nothing..
I had to make a 400 gram weight in it before it could pull a decent train..
0 gauge engines are not scaled to weight in comparison to h0 engines, the only reason they drive better is that the dust on the track (which is 1:1 in h0 and 0 scale) is not a big issue anymore..

[BigJim]

Yes, but when you go to paint it takes four times the amount of paint to do an O vs. HO.

[Anonymous]

Here's the $64,000 question (which is what I think Dave was trying to get at):

IF the real thing weighs 100,000 lbs,

should an O scale model weigh 100,000 / 48^3 lbs, or about 14.5 oz?

Tony

[3railguy]

Yes vitable, roughly speaking. But since the models are electric and mechanically different than the prototype, the result is somewhat off.