I know there’s a NMRA standard for car weights but it really only addresses the recommended minium. Does any have any experience with max weights? I want to start weathering my hoppers and was curious if I could “overweight” them.
The practical limits are what can the axles, wheels and trucks take. For two four wheel trucks, with plastic side frames and metal wheels, keeping the car under 8oz (225gr) is probably a good idea.
Actuall, many modelers feel that the NMRA standard is TOO heavy. The standards were made in the age of heavy brass steamers and lead and brass freight cars, and when O scale reigned.
It’s more important to get the weight of all of your cars to within a consistent range, whether that range is on the heavy or light side. If you have a roster of light cars and add a REALLY heavy one, it might derail the rest of the cars on curves.
Likewise, it’s important to recognize the physical characteristics of your layout. How powerful are your locomotives? How good is your track? How steep are your grades? What is your minimum radius? How long a train do you want to run? All of these factors should be taken into account when deciding on car weight.
I was just wondering about this myself. I was assembling some Branchline Trains boxcars and was suprised at how much weight I had to add to bring them up to NMRA standard. Can others confirm that these standards are still applicable?
By the way, the NMRA standards state that the recommended weights are not just a minimum but an optimum–much weight over and above that and the cars only increase drag.
IIRC, John Armstrong ran some ore cars loaded with real iron ore on the Canandaigua Southern. Don’t know the actual weight, but I’ll bet it was WAY more than the NMRA recommended weight for equivalent O scale cars.
Running cars much lighter than NMRA recommended weight, especially long cars, can cause problems on curves. All it takes is a couple of featherweights at the front of a long freight to make stringlining (pulling off toward the inside of a curve) a distinct possibility.
There was also the problem that the air retarders on Ed Ravenscroft’s hump yard would blow lightweight cars uphill…[:-^]
Chuck (modeling Central Japan in September, 1964)
I’ve got a string of 12 coal cars that are hauling actual coal. I also have a string of 12 ore cars hauling real rock. Are they heavier than the other cars? Yep! Ever cause a problem? Well, you have to double-head the train to make it up the grades, but that’s how it’s supposed to be, right?
Mark in Utah
I was going to ask about loading hoppers and such with actual material, but you beat me to it. How’s it working out for you? Do you have any problems with couplers breaking?
About the car weights, it all depends how you want to run your pike. As per the NMRA standards, that is done so as to make John A’s and John B’s freight cars interchangeable without fear of coming into compatability problems. Obvious with the use of the term “standards”.
Actually with todays longer wheel base cars RP20.1 is outdated…RP20.1 needs to be updated by a better and more equal weight system…
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Chuck said:Running cars much lighter than NMRA recommended weight, especially long cars, can cause problems on curves. All it takes is a couple of featherweights at the front of a long freight to make stringlining (pulling off toward the inside of a curve) a distinct possibility.
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None of the 5 local clubs follow RP20.1 and have no problems except on EXTREMELY LONG trains of 80 plus cars but not on the more average train length of 25-30 cars…
I also believe some of the “stringlining” problems can be caused by poor train handling skills by the operator…
Which of the Branchline cars are you doing? I’m currently in the midst of building a whole lot of the Blueprint Series; these have a couple of huge nuts to use as weights. To me it seems the BL cars are heavier out of the box than just about anyone else’s. I haven’t put them on a scale to measure their actual weight.
That being said, I generally like my cars a little on the heavy side. Tends to make it easier coupling up by engine power. I use Kadee couplers and some times the knuckles don’t join without the car to be picked-up rolling down the line.
As to light and heavy cars in the same train, real railroads have to deal with that as well. Put the heavy ones at the front and the light ones at the rear, in general.
I’m not Mark, but I can take a stab at your question. With properly mounted metal Kadees (at least in HO), with proper train handling, you’ll get wheelslip on the engine before you’ll break a coupler. I know some of the KD clones have had breakage problems doing this. Been there, done that, as they say.
Jack said: As to light and heavy cars in the same train, real railroads have to deal with that as well. Put the heavy ones at the front and the light ones at the rear, in general.
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If it was only that simple…Prototype freight trains are classified into destination blocks and this includes empties and loads in the same block.Oddly when we use car cards and waybills we end up with light and heavy cars mixed together just like the prototype.[:D]
I built three Branchline boxcars, and they did have 2 large (1/2"?) nuts to use for weights. I ended up adding an additional 4 smaller (3/8"? - don’t have them in front of me to check) nuts to bring them up to NMRA standard. In future I think I’ll just add 2 extra nuts.
I’ve had absolutely no problems with Kadee couplers. I glue the coal or rock in place with the same glue mixture used for ballast. These cars are decidedly heavy, and are great to use as the first cars in any long train you want to put together.
Mark in Utah
Thanks all for the responses. I know some modelers that will add the extra weight so the operators have to actually control their trains. That why I was curious if you cold over do it.
When I started the min rec wt was 3.5 oz for a 6" car w/ 1/2 oz for each additional inch. I run 40 to 50 car trains w/ no problem. As for maximum wt, I have one (very) old Roundhouse 40’ hopper that was made when the entire car was cast metal. I don’t know how much it wieghs but it’s for sure more than 3.5 oz. No problem w/ the compressed air retarders on my hump.
For the past 10 years I’ve had success without adding extra weight. I started running a string of light cars with no additional weight to test trackwork on a new layout and was suprised to find that they tracked excellently. So I kept running them light and have ceased bringing new cars up to recommended weight. Even when lightweights (1.9 oz.) have hevyweights (7 oz.)randomly mixed in, everything still tracks fine.
Part of this success is due to today’s excellent track and trucks. I also make sure that all equipment – trucks alone, trucks attached to their car, and strings of cars --will start to roll and continue to roll picking up speed on a 30" R. 2% grade.
By the way, those 7 oz. cars are interchanged with a traction line where their weight is necessary to throw spring switches and to keep them on the track when their radial couplers are trying to pull the car ends sideways.