Skip to main content

This is inspired from the post on Märklin using magnetraction. There it was stated that an O scale AC6000 would weight 8000 pounds. 

The discussion of an 8000 pound O-scale locomotives have me thinking about what it would take to get an 8000 pound Lionel GP35.

https://ogrforum.ogaugerr.com/t...95#45918751637014495

 

 20151124_125029

 

This is a picture of a Lionel GP35 next to a 25 pound dumbbell weight. It does not take too much imagination to see that they are roughly the same size. Thus, if the Lionel GP35 was made out of solid iron it would weigh approximately 25 pounds. Just an approximation, need not be exact. 

 

Iron has a density of 7.874 grams per cubic centimeter. Most of you do not deal with grams and centimeters too often so I will change that to pounds and inches. A centimeter is about 2/5 of an inch. The density of iron works out to be 0.017 pound per cubic centimeter or 0.266 pound per cubic inch (abbreviated lb/ci from now on). Unusual set of units, but hopefully approachable. Pounds in this case is the engineering pound-mass. The pound-mass is how much matter something contains. When one weighs themselves, they are using the pound-force. The two are different. In Earth’s gravity, the pound-force and the pound-mass exerts the same force on the surface. However, one pound-mass on the moon exerts a force of ~0.2 pound-force on the moon.

 

The densest material on the surface of Earth is Osmium which has a density of 0.777 lb/ci. If Lionel were to make the GP35 out of solid Osmium the locomotive would weigh 71.76 pounds! Heavy, but far short of 8000 pounds.

 

So let us take the material out of Earth’s core and make the GP35 out of that. Well, Earth’s core has a density of about 0.447 lb/ci which would give the GP35 a weight of 41 pounds. That does not work.

 

So let’s use the core material from our largest planet. The density of the core of Jupiter is approximately 0.86 lb/ci. If Lionel were to make the GP35 from the core material from Jupiter the locomotive would weigh 79 pounds here on Earth; still far short of the 8000 pounds.

 

It seems that there is no planetary material to make our locomotive out of to get our 1:48 scale GP35 to weigh 8000 pounds. Let us try stellar materials, or the stuff that makes up stars.

 

Red dwarf stars are stars are bodies the fuse hydrogen in their cores and are between ~7.5% and 50% the mass of the sun. These stars are very small and the red dwarf stars that are 10% (~100 Jupiter masses) the mass of the sun are about the same size as the planet Jupiter! They are very dense. Proxima Centauri which is ~140 Jupiter masses is only 20% larger than Jupiter and has a mean density of 1.93 lb/ci. Thus, if Lionel made its GP35 out of red dwarf star material it would weigh about 180 pounds! Not there yet.

The overall density of Sol (our solar system’s star) is a little over 0.03 lb/ci.  However, the core of Sol where the fusion of hydrogen nuclei takes place has a density of 5.16 lb/ci! The core is under a lot of pressure which makes it denser. If the scale GP35 was made out of solid core material of Sol it would weigh 476 pounds on Earth! Not even the material from the core of the sun would give our GP35 a weight of 8000 pounds.

 

How about the core of Betelgeuse, the red star in Orion’s shoulder. It is 10-20 times the mass of Sol and has an estimated core density of 26 lb/ci. If we were to make the Lionel GP35 out of solid core material from the star Betelgeuse it would weigh roughly 2400 pounds here on Earth. OK, now we are in the neighborhood. To make our Lionel GP35 weigh 8000 pounds would take producing the locomotive from the stellar core material of a very massive star; most likely an O-class star.

 

We can take this further: white dwarfs with a density of 34,000,000 lb/ci. If we were to make the GP35 out of the degenerate material from a white dwarf start (our sun will become a white dwarf ~5.2 billion years from now) our GP35 would weigh 3,000,000,000 pounds on Earth.

 

Neutron stars are the core remnants of large stars.  Betelgeuse will become a neutron start in the future. Neutron stars have a density of 3,000,000,000,000,000 lb/ci. Our GP35 would weigh 330,000,000,000,000,000 (that would be 330 quadrillion) pounds here on Earth. If you were to pick up the GP35 and accidently drop it onto the ground the energy released would completely destroy the North American continent. The GP35 would sink through the ground until it reached Earth’s core.

 

 

Attachments

Images (1)
  • 20151124_125029
Last edited by WBC
Original Post

Replies sorted oldest to newest

Originally Posted by OGR Webmaster:

I got caught in this mistake a few years ago.

 

Because we scale down to 1/48 scale in THREE dimensions, the "correct" weight for our model is it actual weight divided by 48, that result is divided by 48 again and that result is divided by 48 yet again!

 

430,000/48 = 8,958

 

8,958/48 = 186

 

186/48 = 3.875 pounds

Yep.

 

But it has been difficult convincing some on the other thread.

 

The whole point was to show that it was physically impossible to use any material here on Earth (or even our solar system) and have a 1:48 scale model of an AC6000 weigh 8000 pounds. 

According to a booklet I have (The Complete Steam Locomotive Companion by Fletcher Cox), N&W 611 weighed 494,000 lbs with a fully-loaded tender of 378,600 lbs, for a total of 872,600 lbs.

 

Using the above formula, that comes out to approx 8 lbs in 1/48 scale.  My Williams brass J weighs 14.2 lbs (has a LARGE chunk on lead inside the boiler), that's 75% over weight

 

My J needs to go on a diet

Jack and Rich are correct. Weight is proportional to volume; that is, a cubic function consisting of width x length x height. In our case, as Jack and Rich stated, 48 x 48 x 48 or 48 raised to the third power, "48^3" as in Excel and other programming notations.

 

48^3 = 110592

 

Divide any full scale weight by 110592, and that would be the weight in 1:48 scale. The example of 430,000 lb when divided by 110592 yields 3.89 lb.

 

By the same token, a 10 lb O-Gauge locomotive would weigh 1,105,920 lb in real life.

The real Big Boy and its tender weighed 1,250,000 lb, or almost 11.3 lb in O-Gauge. (I don't remember how much my Big Boy weighs.)

 

Alex

Last edited by Ingeniero No1

baltimore..."free shipping". Har.

 

====

 

Anyway, a million years ago (1980's) I did a rough calculation on the weight of my then new and zoomy scale Lionel 785 gray Hudson (we've come so far), my first "big, scale" steamer, and, though I forget any and all of the actual numbers, it seems that the model's weight was very roughly what it should be for a J1e Hudson.

 

It was probably wrong, though, as most of our die-cast models are too heavy to be accurate; I imagine that plastic diesels and brass, not-too-weighted steamers are closer.

 

Interesting subject, anyway.

Okay now take that 25 pound dumbbell, put it in a hypothetical hydraulic press that can reduce it down to half it's size by squeezing the iron atoms closer together while maintaining the dumbell's original, relative shape & proportions.  Does the dumbbell come out of the press lighter after you've done that?  Of course not.  Why? After all, it's now half as large as it once was?  The answer is because you've not taken any iron atoms away when you reduced it's dimensions, so its mass will remain the same, although it's density will be slightly, albeit negligibly, higher in this particular scenario.


Here's something else to consider.  Suppose you took the dimensions of a lake in the real word and made your own version of it, scaled it down to O size and use real water, does the consistency of the water "scale down" so it's not near-Jello like for the O scale world because you use less water?

 

Just as an aside to WBC's statment:  As the late astronomer and cosmologist Carl Sagan was known for saying, that pretty much is agreed upon in cosmological science, is that everything in our known Universe are made from the aftermath of exploding stars (supernovas), so everything, is in effect star matter such as carbon, hydrogen (being the most abundant element in the known universe) along with nitrogen, helium, oxygen and other, heavy elements like iron and magnesium (hey, we got those in our bodies too).  The elements at the core of a dead or dying star, where the gravitational pressure due to the gradual loss of the counteractive forces provided by helium and causing such extreme densities WBC outlines, are the same as those from other stars, again being carbon,  hydrogen, nitrogen, and other.  They all are made up of the same "stuff."  Some are just under more gravitational pressure than others. 

 

It's not absolutely "impossible" to not be able to replicate the density of a full-size prototype locomotive if you were able to shrink it down without losing any of its mass, in science nothing is absolute.  It more accurately can be said it's currently not possible, improbable perhaps; but in science disciplines, absolute claims are never, ever made.  If any one scientist makes a claim something as an absolute, then they either are lying, or they're omniscient.  Due to as what's so far been demonstrated by the human species' ability with the later I'd be inclined to believe the former. 

 

 

 

Last edited by John Korling
I remember reading in Model Railroader where they mathematically determined how much a HO scale UP Big Boy should weigh and it turned out to be about what a out of the box HO scale one they had weighed. I don't recall the math they used but it sure wasn't a % of the real-life weight to the scale of the model.
 
Originally Posted by gunrunnerjohn:

Remember, the rolling resistance of our model cars is probably far in excess of a real train car if you scale it up to full size.

Yep, you can actually get a freight car rolling on level track with about ten people pushing on it, and it doesn't take much to keep it rolling once it's moving. I personally once took part in moving an empty boxcar exactly in this manner.

Originally Posted by OGR Webmaster:

... Because we scale down to 1/48 scale in THREE dimensions, the "correct" weight for our model is it actual weight divided by 48, that result is divided by 48 again and that result is divided by 48 yet again!

 

430,000/48 = 8,958

 

8,958/48 = 186

 

186/48 = 3.875 pounds

That makes perfect sense.

 

From a practical standpoint, we just want model trains that are functional and operable and reliable. HO scale has good NMRA standards for fairly uniform weight adjusted to length, and the better hobby manufacturers generally seem to follow this. Older O-gauge items that I am familiar with have a lot of variation in weights.

Hi John,

 

We went through this once before, didn't we?

 

The title asks "How much should our trains weigh?"

 

Our trains are models, and a model is not an original object compressed down to a smaller size.

 

It is a completely different object, in most cases made out of different materials from the prototype. The materials used have the same normal properties as any other earthly materials and so. They are simply fashioned into an object that "looks" like the original. Therefore, they weigh approximately the 1 over 48 cubed of the prototype already mentioned.

 

Now, if you ask, what would a 200 ton engine weigh if it were "compressed" down to O scale dimensions - that would be a totally different question and have nothing to do with modeling. It would still weigh 200 tons, as you say, ignoring the impossibility of that compression process as WBC pointed out.

 

It does bring up the question of how the surgical team, plus submarine, were miniaturized in the movie "Fantastic Voyage" before being injected into that guy's body. If they were just compressed and weighed the same, it would have been more than a little tough on the patient's body.

 

Jim

 

Last edited by Jim Policastro

Add Reply

Post

OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
800-980-OGRR (6477)
www.ogaugerr.com

×
×
×
×
Link copied to your clipboard.
×
×