I’ve got another one for the fourms. When putting weight on a car, I know the standard for HO is 1 oz plus 1/2 oz for every inch. How close is close enough to this standard? I have some 34’ hoppers that when empty weigh 3.3 oz. The standard says they should weigh 3.75. However, when I put the load in these cars, they then weigh 4.8. (Yes the loads are that heavy. I double-checked it on the scale.) Is that .45 oz enough to cause a problem when the cars are empty? Thank you for any assistance the forums can provide.
If the empty cars are between the locomotives and the loaded cars, then they might stringline on the curves. However if you just have empty cars on one train, and the loaded cars on another train, then it should be fine. If you can easily add weight to the empties, I would suggest bring them up to the standard.
Too little weight might cause the cars to derail. Too much doesn’t cause any problems, except maybe reduce the number of cars a loco can pull. Too much weight could be a problem if you have grades on the layout. Better too much, than too little.
By the way, I have cured a number of derailment problems by just adding weight to the offending cars.
You could run the empty hoppers at the end of the train. If your running them “loaded”, place right behind the locos. I have a train of hoppers I run as a frac sand train, since the “loads” were sculped and painted, using styrofoam, they added no weight to cars. I had problems with “leaning” on curves, almost to the point of string lining. I added weight to each car, bringing them to within 1/4 oz of recommended weight, (hid under the foam “sand” loads, and the cars trail perfect.
I’ve also added weight to passenger cars to get them to run better, and work better for “push-pull” operations.
I guess you have to experiment.
Mike.
There are many variable factors. Length of train, grades, curve radii, train handling. etc. My personal experience running 35 car trains with 36" curves and 1.5% grades is even though it is short of the NMRA figure, 3 oz. for an empty hopper or flat car is plenty. I do shoot for the standard you mentioned but it is hard to achieve with some cars.
The real railroads had a problem with empties on occasion too. Imagine a bunch of lightweight empties in a train going up and around something like Horse Shoe Curve. With a pair of snappers shoving for all the were worth, if the head end power fell down, it might just be accordion time.
Charlie
There is no grade in the area where they would be operating, train would be fairly short and would not be going at any great speed (the part of the railroad where the cars operate mostly yard with a short mainline run to an unloading track), curves are 22" R.
The plan is to eventually have nine of these cars operating in three sets of three each.
I follow the recommended practice plus approx. one ounce. Works fine for me.
That small a difference, really anything less than an ounce, should not affect the performance unless it as a marginal performer that was helped by adding a little weight. As was mentioned, the prototype had issues with empty cars, although the disproportionate difference in weight between MTs and loads is much greater there.
But don’t use weight as a crutch to avoid checking out a problem car. Usually there is something that needs attention. Adding weight is a band-aid approach to problems. And if you have significant grades or motive power with limited traction, adding that weight hurts operations. Sometimes after all is checked over, yes, you need a little extra weight.
What’s most important is consistency. If they are all within an ounce of each other, there’s very little chance weight becomes an issue.
That’s cool. But it would be a killer in narrowgauge. We often underweight cars, because of grades and limited tractive effort in our small locos. But we do it consistently. Works fine, so long as your track is up to snuff and your cars are in spec and rolling well.
My empty hoppers (Athearn) weigh just over 2oz., but tip the scales at 8oz. when loaded. A train of solid empties runs fine, as does a train of solid loads, and coal trains always run in that manner - all loads or all empties.
When hoppers are interspersed in mixed freights, a loaded hopper or two cause no problems. If an empty hopper or two is moving within such a train, I try to place them near the rear - just another way of adding operational interest.
Such heavy cars can be a problem on grades, although I see them as an opportunity (excuse) to doublehead such trains. Most of my layout is on grades, and most of those are on curves, so the grades are the equivalent of about 3.3% - enough to keep coal trains to 12 cars, plus the caboose. [swg]
One locomotive brings the coal in from the interchange:
…and a second loco is added about a half-mile later, just before the grades begin:
Wayne
Here’s my thoughts…RP20.1 is outdated due to the fact it was for 40’ cars with the modern cars ranging from 42’-89’ not a good idea since the weight is all over the place due the various inch length of these cars.
I started a weighing project where all my cars Will eventually weigh the same 4 oz regardless of its inch length as was suggested in a operation clinic I attended-probably the best $10.00 I spent is a long time snce the clinic covered several layout operation methods-including the “you go/I go” method used on DCC point to point layouts that lacks working signals.
I think you will be fine. I don;t have any extra weight in my open hoppers, and when I put loads in them, they are alo well over weight. I’ve run them empty at the head of a train of closed cars that all do check in nearly right on NMRA weight, and even with sudden unexpected stops and starts on curves when someone else shorts that area of the layout, I’ve never had them stringline. It takes a very light car, very charp curves, and some really awful handling to get model cars to stringline (though going gtom 30 to 0 and back to 30 instantly probably qualifies). Your cars should be fine.
–Randy
I regard the NMRA weighting standards as a goal to be met, but in actual point of fact if there is “good weight” in the cars some variance from those standards does not create huge operating problem assuming good track and reasonably free rolling trucks (indeed a case can be made that the smoothness of track and curves, including easement curves, the rolling qualities of the trucks, the ability of the trucks to swing freely on the bolsters, the center of gravity of the cars, and coupler swing, are all variables that have so much to do with good tracking that weight of cars alone may well be over-rated as a factor.
I suspect very few flatcars or gondolas for example are able to be weighted to NMRA standards – and I say that as someone who replaces steel with lead weight, wraps the axles with solder when possible, and crams bits of lead into the underframe and even so my flatcars and gons are underweighted. The center of gravity of a flat car is low and I for one simply do not experience the problems so long as there is SOME degree of appreciable weight to the cars. My house cars tend to meet NMRA standards exactly. Some tank cars are a challenge as well.
I have large radius curves and I think full length passenger cars weighted to NMRA standards might be a bit excessive. Consistent weight is more important in my view, and of course I do not mix freight and passenger cars in the same train.
Dave Nelson
Car weight is not an NMRA Standard, it is only a Recommended Practice. As long as a car doesn’t derail I don’t weigh them. If one does derail more than once, then I look first at wheel gauge, then tightness of the trucks, and finally the weight.
For flat cars and gondolas, it’s often possible to remove most of the underbody detail, including the frame, if the car has dropped sidesills.
This Walthers flatcar retains its frame, as it’s actual a visible part of the car, but I custom-cast lead weights to fit into the voids between the frame members. The car, empty, weighs 6oz.:
Athearn flats, like the one below, modified with bulkhead ends from the Walthers cars, have both the frame and deck removed. The area formerly occupied by those receives a new sub-deck of .060" styrene, with its top flush with the top of the car’s sidesills. Contact cement is then used to add a deck made from stripwood:
The underside gets a block of cast lead, held in place by styrene strips and silicone caulk, bringing the weight up to about 6.5oz.
Wayne
I use the NMRA RP vaalues for the HO cars
BUT !
I convert everything to Grams!
It seems a bit more accurate to me as I prefer to get the car as close to the recommended weight as possible!
Now on Flats and Gons - some can be weighted and I usually use #12 Lead Shot (which is the smallest redially available)
I will pour the Lead Shot into any opening in the fram or underside I can and then use diluted Mat-Medium to glue the Lead Shot in.
BOB H - Clarion, PA
I find that weight is less important than having free rolling accurately gauged trucks. Not that weight doesn’t matter, you just have more leeway with the trucks tuned correctly.