Doodlebug (Walther / Spectrum)

Your calculation is wrong!

The model loco would only weight the inverse CUBE of the scale factor ... that is, in HO, 1/87 X 1/87 X 1/87 = 1/658,503 of the real loco. Thus your 70 ton loco in HO should weight only 70 X 2000 lbs/ 658,503 =

0.212 lbs., or about 3.4 oz. Most HO locos are far heavier than that.

Dan Mitchell ============

Reply to
Daniel A. Mitchell
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Make that a 150 ton loco ...so: 150 X 2000 / 658,503 = > 0.45 lbs. = 7.3 oz. ... and MANY HO locos are heavier than that.

DM ==

Reply to
Daniel A. Mitchell

Betcha can't squeeze a pound of potato chips into the same box that held a pound roll of solder.

Walt

Reply to
Xtrachesse

snip

I look at our grades as a form of selective compression. A 2% model grade is used to represent prototype topography that would not be nearly as steep. To compensate, model tractive effort should be much higher than scaled prototype performance (as you say).

Reply to
David B. Redmond

How many dimensions do I get to use? *8->

xtrachesse was talking in pounds. Geezer responded in mass. If Geezer is correct:

I can.

What is the volume for a pound of, a slightly imperfect, vacuum?

Paul

Reply to
Paul Newhouse

Black holes (depending on how you define one) have INCREDIBLE mass (some have millions of solar masses), but NO volume (the 'singularity"). That implies infinite density. There seems to be no limit on how much 'stuff' one can pack into NO volume.

More precisely, the 'singularity' at the center has ZERO volume and contains by far the majority of the mass. Surrounding it is an 'event horizon' of finite size (rather the size of a planet) that contains the singularity. The 'surface' (if you can call it that) of the event horizon would be seen (another conundrum) to be the visible (?) surface of the black hole.

Within the event horizon there is some additional mass descending to oblivion at the singularity.

So, mass is NOT a function of volume. Indeed, mass warps the space around it, alters dimensions, and changes the whole concept of 'volume'.

Dan Mitchell ============

Reply to
Daniel A. Mitchell

Same problem arises in Gulliver's Travels....

Reply to
+GF+

Dan,

I think a number of us understand problem with the orignal, mass is volume statement.

Paul

Reply to
Paul Newhouse

In full size, the weight of a locomotive is finally dependent on its allowable axle load, and this in turn is dependent on what the track will take before it fails. On a model, the possibility of the track failing (rail breakage, rail turning over, bridge collapse etc.) is pretty much zero. So, equivalent axle loads on model locos can be much higher than on full-sized locos, and this has been demonstrated in earlier posts to be so, with their comments about model loco weights, which are also equivalently much higher than their full-sized counterparts. So, while most model locos should in theory be able to haul greater numbers of cars than their full-sized equivalents, this is negated by the much higher friction of model cars, probably equivalent to a full-sized train with half the cars with their brakes on. Regards, Bill.

"David B. Redmond" wrote in message news: snipped-for-privacy@4ax.com...

Reply to
William Pearce

I think that it is safe to assume that nobody here is planning to build a model railroad anyplace other than on the surface of the Earth, so for all intents and purposes they are interchangable.

Reply to
Jason Davies

I think it's safe to assume that no one is planning on using a kilo of hard vaccuum to build a model railroad... or that they're likely to come up with it on Earth. So, no, they're NOT interchangable.

Reply to
Joe Ellis

I don't think it's that simple. Remember we're talking mass/weight, which is also dependent on volume. Since we're talking three dimensions, you'd need to divide the prototype weight by 87 CUBED to get the "scale" weight.

150 ton = 300,000 lbs, ÷ (87 x 87 x 87) = .455 lbs., or about 7 1/2 oz.

Well within the nominal range for HO locomotives, in fact many newer engines weigh twice that much.

Don

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Reply to
Trainman

1 kg of anything likely to be used on a model railroad will weigh 2.2 pounds.

If somebody decides to put live loads in a helium car OTOH...

Reply to
Jason Davies

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