Dose annyone know of a prototype to HO scale weight converson? Example…How many oz. do I need to add to my coal hopper to simulate a 100 ton load of coal?
I don’t think there is a way to scale down weight. Strictly speaking, HO is 1/87 so a 100 ton load would equal 100/87 or 1.15 tons. Probably not going to find enough locos to pull it or an HO scale car to hold it. The only thing I can offer is that if you were to use crushed real coal, fill up a coal car, you would in fact have a scaled down load.
Rick
I think you are asking the wrong question. The question should be, “How much should my cars weigh so that they track well, conform reasonably to NMRA guidelines, and don’t bog down my engines such that I can only tow three so weighted cars up my 1.8% grade?” In other words, you should avoid weighting the cars to simulate loaded ones because they will impose more wear and tear on both them and your drawing locomotive, generate that much more heat under the shell due to the amperage the motor demands to do all this extra work, and so on. That is why the “better” cars are properly weighted when you get them, plus or minus half an ounce, and why simulated coal loads are not actually full volume shapes of black glass shards…which would be very heavy. Instead, they are usually thinly molded plastic. In my case, I used a thin wafer of extruded foam on which I poured a thin covering layer of the same black glass bits of “coal”, and glued it into place.
If I recall, the proper weight for empties is 1.5 oz, plus and additional 0.5 oz per linear inch of body length. If your cars come that way, and you add another 3-4 oz of coal to them, you are going to have to cut your train length nearly car for car.
Selector is right that the standard HO car weight is 1/2 oz plus 1/2 oz per inch of length.
A prototype car which weighs 35 tons empty, when reduced to HO scale (cubic reduction) would weigh 1.7 ounces. A 100 ton load of coal, or 4.85oz, would bring the loaded car to 6.5 (close enough) ounces - the weight the NMRA recommends for a passenger car or hi-cube, but not really out of line if you want your Y6 to do honest work.
In practice, a full load of pool filter charcoal might add one ounce to an empty three bay (70 ton) HO hopper. I don’t know if real coal can be crushed fine enough to actually get close to 5 real ounces into a Bethgon or equivalent - mine run coal would be about equivalent to household dust with a few grains of sand mixed in. Even 3 inch lump coal would have particles less than 1mm in any dimension.
Chuck (modeling Central Japan in September, 1964 - including two working collieries)
I too would use 87 cubed, which equals 658503. So, 286,000 pounds for a real car would be 0.4343 pounds, or 6.9591 ounces, for HO scale. Of course, as already mentioned that is not how car weight is determined for model trains.
Was recently thinking on just this idea myself- adding weight to cars to simulate loads vs. empties. The ratio of load limit to light weight seems to me the way to go. Load limit of 207600 to light weight of 78400 is approx. 2.65, for example. So a fully loaded car couldn’t weigh more than 2.65 times our scale empty weight? Works for me (which usually means there is some simple, fatal flaw in reasoning!).
How would this weight compare to some of those mentioned? The same ratio idea would mean that about 20 empties would equal about 7 loads… That could have an impact on the number of locos required!
Outstanding, thanks for correcting my faulty math. I forgot about the cubing the number due to a volume measurement. DOH!
Rick
Probably with the small radius curves we use in model railroading, stringlining might be a problem.
But with easements, and broader curves… and loads would have to be up front, any empties at the rear… smaller radius would mean shorter trains at slower speeds… sounds like some interesting operating possibilities.
I don’t have a scale- anybody know what typical n scale car weights are? And what to use for adding the weight? I’m guessing car weight about an ounce or two?
Here are the NMRA recommendations http://www.nmra.org/standards/rp-20_1.html.
Not sure what will fit for N scale. In S scale I use pennies and have used small nails, but BB’s, lead shot(potential health hazard), commercial weights could be used. I have some metal cows I plan to use in a wooden stock car.
Enjoy
Paul
Ironrooster, thanks for the info. Looks like my fully loaded 50’ boxcar weight would be around 2.75 ounces, if the starting weight is 1/2 ounce + .15 x 3.75". I’m going to add some weight and see how it works. (To the cars, that is- I added enough weight over the holidays!)
No. The starting weight for a car is one point five ounces (1.5 oz), not 1/2 as you state. Thereafter, you should add 0.5, or 1/2 oz per inch of car length, not 0.15 as you state (zero point one five, or 1/6 of an oz). Your weights will still be inadequate if you use the figures you state above.
I’m not clear on this - the figures used are from the standards link Ironrooster provided. Where does the 1/2 ounce per inch of car length, and the starting weight of 1 1/2 ounces, come from? I can accept that actual car weight is going to vary, but what’s up with 1/2 ounce versus .15 ounce/ inch? And when it gets down to it, all my premise is saying is that a load should weigh about 2.6 times an empty.
Hi. When I click on the link, I see a table, down low, that says HO cars are meant to start with 1 oz of initially added weight, and then in the right column it clearly says “.5 oz”. The column is headed with the words telling us that the additional weight is for each inch of body length.
You said .15 oz, and that is roughly a sixth, not a half.
I had always understood that the initial weight was to be 1.5 oz, but I see that this linked table has it as only 1 oz. In my opinion, if the table is correct (and why would it not be), then the addition of 0.5 oz/linear body length inch, as the right hand colum dictates, is even more critical for proper weighting.
The table covers multiple scales. You’re looking at the N scale line which is the line you want. The original poster was interested in HO which is 1oz plus 1/2 oz per inch.
Enjoy
Paul
Hey folks, let’s slow down a bit, we have a little confusion here.
cnw400 was asking about N SCALE - for that, the NMRA table says 0.5 oz + 0.15*(actual car body length in inches). So a typical 50-foot boxcar, at 5012(to make it inches)/160 = 3.75 inch length, should weigh 0.5 + 0.153.75 = 0.5 + 0.56 = 1.06 oz.
For HO, the calculation comes out 1.0 + 0.5*(5012/87) = 1.0 + 0.56.9 = 4.45 oz.
And it’s not “initially added weight”, mr. selector, it’s the first part of the formula for total car weight, regardless of how much of it the manufacturer or you put in…
In reality, if you’re within 10% or even 20%, it’ll be close enough.
I use a postal scale to check my weights in HO, and I’ve actually made a small ruler with ounce markings on it, so I can just hold it up to the car and see what the weight should be.
You are correct…my bias towards the original question and my own scale came to the fore. My bad.
As for the “initially added…” I really should have typed “…assigned…”, although they are nearly interchangeable. I must be more accurate.
Regards.
I model in HO and run loaded coal trains. Since I’m modelling the ‘30’s, the hoppers are Athearn 34’ 2 bay, either ribbed or offset sides. They all use the stock trucks and wheels. For coal, I’m using loose locomotive traction grit, a black granular material with a bit of a sparkle to it - probably more like anthracite than soft coal, but it gives a nice visual effect. Weight of one loaded hopper is 8 ounces. Because my passing sidings are fairly short, trains are only 12 cars long, plus a caboose, making the total train weight 100 ounces. I have modified a number of Athearn Mikados for use on this train: a pair of Mikes are required to move it over the division, which includes grades of 2.5% and 2.8%, both on multiple curves. There are no problems with stringlining, although loaded cars can tip on a curve if the trucks are too loose. It also helps that the train is a dedicated move to a power plant, so no other cars are included in the consist. The picture below, of a single hopper being delivered to a coal dealer, illustrates the appearance of the “coal”. For steam locomotive tenders, I use coke breeze, which is basically very fine coke, much of it dust. With open tender bunkers, and loose loads, it’s easy to adjust the amount of coal in the tender, a bonus for photos.
Wayne
A couple of items:
One force behind the NMRA car weight standards was to develop a way to get all cars to have approximately equal rolling resistance. The driving force behind THAT, I suspect, was an NMRA official with an operating hump yard in HO scale. I personally follow the NMRA standards for HO even though I model in 1:80 scale. (Prototypes are smaller, scale is larger, bulk is about the same.)
My car cards include load limit and light weight data. My waybills include the weight of the shipment. Locomotives are assigned by tonnage rating, determined by adding the light weights and shipment weights. Only a string of empties comes anywhere near the actual pulling power of the assigned locomotive(s). OTOH, I now have the ability to “fill to tonnage,” or to leave a heavy carload of lower-priority freight for a later train if the road power can’t handle it.
Chuck (modeling Central Japan in September, 1964)
Since weight is actually a measure of mass in a gravitational field, wouldn’t HO scales equpiment need weighed on a planet with 1/87 the diameter of the earth? Since gravity decreases with the square of the distance, an HO car would need to weigh 1/7569 which is 1/87 squared rather than 1/87 cubed which is actually the volume of a 1/87 scale model and has nothing to do with weight?