Okay - I"m getting closer to having a running railroad and now I need to know how seriously to take the NMRA weight standards. Does everyone use them? Should I follow them to the letter (or number) or are there cars that are ok to be heavier or lighter than what their formula would say is optimal? I’m in HO and so I"d be using the 1 oz plus 1/2 oz of each inch of car length. Thanks.
Stick with the standards, give or take maybe a quarter ounce. You’ll have a happy railroad.
Nope…Never did and never will seeing they are outdated.
I agree. Too light and too heavy can cause trouble. And don’t forget gauging your wheels, tuning your trucks and checking your coupler heights. All this “busy work” ahead of time leads to a lot of enjoyment later.
Joe
If you install metal wheelsets and good rolling trucks you can reduce the NMRA standards a bit. Install the weights at floor level and not under the roof.
Ted, before I started using the standard I had nothing but problems on trains over 10 to 14 cars. If you have 28 inch turns you might not have a problem. Where the extra weight helps is in 18 inch turns. If car are to light they will tip over.
Key to happy rolling stock is.
1 Free wheeling trucks and metal axles
2 Proper weight
3 Proper coupler height
If you are missing anyone of this points, you will not enjoy your RR as much.
Learned the hard way myself.
Cuda Ken
Hi Ted,
I do my best to have all my cars match the NMRA recommendation (RP-20.1 is a recommended practice, not a standard). In my experience trucks, couplers, and trains all perform better when cars are consisently weighted.
So long,
Andy
I go with the NMRA standard. I use a cheapo kitchen spring scale to weigh my cars on. A couple of cases of repeated derailment just went away after weighting the derailing cars up to NMRA recommendations. Bolts, nuts, bits of metal scrap weight my house cars (where the weight is not visible). Sheet lead flashing from the hardware store makes a low profile weight that doesn’t show much. Dow Corning bathtub caulk will stick a weight down good and hard.
Yes I do, even though, like Brakie, I think they are outdated. As another prior poster noted, the technical quality of our equipment is so much better than when these standards were decided upon they are “heavy” in my opinion. When I do follow this standard I can carry my rolling stock to other people’s layouts and know it will work with theirs. If I ran mine lighter, as I think they should be, this interchange could cause problems. Likewise when other people brought their equipment to mine there could be issues.
Yes, to the letter. What would be the point of following a standard, but then not really following it? The formula has a built in plus/minus factor (1/8?oz).
I certainly keep my cars weighed to the NMRA recommendation, and always on the + side. On my layout, more weight equals less derailments. As easy as that.[:-^]
I do.
The consensus seems to be to use the NMRA guidelines, at least as a starting point, which is what I’ll do. Thanks everyone.
Ted
Except for my heavyweights, I use them as they come out of the box. In fact, if one or more cars doesn’t like staying in the rails when in my typically short trains, there is something wrong that needs scrutiny. The trucks aren’t pivoting properly, one or more is warped, the axles aren’t seated properly, the sideframes need attention from The Tool, couplers are out of kilter…it goes on. If I find nothing wrong with the car(s), they get more weight…first rule.
As some of us agreed to in a recent thread, heavyweights come by their names honestly. With metal strips, lighting rigging, metal trucks, and long robust bodies, these require horespower. I don’t happen to like or want interior lighting, so I ripped all the related stuff out of my Walthers heavies and lightened them up considerably. I also used Dextron III automatic transmission fluid on the axle ends to lube them a bit. They still track very nicely, although my curves are in the 32" range and well beyond.
-Crandell
I follow the NMRA weight recommendation.
Personally, I think I get better performance.
Enjoy
Paul
The concept of NMRA RP20.1 is sound, that a longer car should weigh more than a short car. Whether you agree with the actual figures or not is not relevent over your entire fleet. Within a given train set, like all your Superliners or a bunch of hoppers used in a unit train, the weight needs to be consistant from one car to the next, and is more important the longer your train gets. I generally follow RP20.1, but my empty hoppers weigh less than the loaded ones, just like the real railroads. I picked up a cheap digital postal scale (about $20) at Staples a couple years ago and use it to weigh the cars.
Yes, I use the NMRA weight. In my experience it’s better to have a car heavier than the NMRA weight standards than lighter.
Wolfgang
Our club car standards include proper weight to NMRA recommendations, all metal wheels that must be free-rolling and all metal couplers.
When running 40-50 cars up 2% helixes, operational reliability requires everything to be up to a certain standard.
I think there is a legitimate difference of opinion as to whether the RP is too heavy or not. Personal experience and opinion suggests that full NMRA RP weight helps the following:
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if you use sprung trucks, the springs don’t “spring” at too light a weight. That said, many sprung trucks could use wimpier springs.
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light cars can “bounce” instead of coupling with automatic couplers. This is particularly true in HOn3 and N
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similarly, light cars have a tendency to do the “Slinky” if they have really free rolling trucks. The Slinky dance gets accentuated if you use the scissors style knuckle couplers (N, HOn3, Kadee #711)
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pushing lighter cars is more derailment prone. Weight helps more with pushing than pulling.
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light cars are more prone to string lining. Curve radius has the biggest impact on string lining. But if you have smaller radius curves - 22" or less - the full NMRA weight can help prevent string lining.
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compatibility with club rules. Many club rules require cars be weighted to NMRA RP.
Reasons not to use full NMRA weight:
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heavy cars overload engines, especially on grades. With the advent of sound and plastic superstructures, there is less space for weight in our engines and their pulling power isn’t what the metal models of yesteryear had. If you want long trains, especially passenger cars, your cars need to be lighter.
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heavy cars wear rigid plastic truck sideframes faster
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trucks are more free rolling than they used to be, and have improved flange profiles, reducing the need for so much weight
I do not use the RP. A weighted car is an excuse for bad track. Fix the track and your tune up the rolling stock. Coupler hight, trip pin hight, free rolling wheels, wheels that are in guage and trucks that swivel freely on good layed track with no kinks or reverse curves are way more important than weight. The only thing on rails that need weight are locomotives. When the modules are set up at shows the track dips, rises, is off center, and other problems that portable layouts experiance. I have fewer problems with long strings of empty hoppers than some with short trains of weighted cars.
Pete
Pete: try running a really long train with a bunch of really light cars in front of a bunch of heavier cars up a helix with a 2% grade. Weight matters. If you’re only running on flat modules, then maybe it doesn’t matter, but if you have a permanent layout with grades and curves, then you’ll want everything to be rather consistent. Having the trucks swivel properly is also very important, but a really light car will stringline in a helix when there’s 30-40 more cars behind it, like in our club layout. That’s not a track problem - it’s a car problem.
Also, the key word is consistency. If all the cars in the train are identical but light, you shouldn’t have any problems. It’s when you mix light and heavy cars that you start asking for problems to occur. The same thing happens on the real railroads - just ask CN why you shouldn’t run a cut of empty centrebeam lumber cars at the head end of a really long train through mountainous and twisty terrain. They had a couple derailments like that on the old BC Rail territory shortly after they took over operation of that line.