The nmra car weights question occurred to me. Now i might have missed this. Are those wieght standards for loaded or empty cars?Seams to me they are empty weight especially flatcars and such.
A pessimist sees a dark tunnel
An optimist sees the light at the end of the tunnel
A realist sees a frieght train
An engineer sees three idiots standing on the tracks stairing blankly in space
NVSRR The nmra car weights question occurred to me. Now i might have missed this. Are those wieght standards for loaded or empty cars?Seams to me they are empty weight especially flatcars and such.
That's total weight with no distinction between loaded/unloaded. The weight presumbably yields optimum performance trading off between rollability vs drag on the locomotive.
Several people over the years have argued for less weight, usually so more cars can be pulled - especially up grades.
Others have argued for more weight to help the cars stay on the track or for more realistic coupling/uncoupling performance.
Personally, I have found that weighting my cars (and loads if any) to the recommendation works very well.
Paul
The NMRA Recommended Practice is for the mode, whether it is modeled as being loaded or not.
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I do not use the NMRA guidelines, but I have a simpler system:
Cars 40 feet and below: 4 ounces
Cars around 50 feet: 5 ounces
Cars 60 feet or more: 6 ounces
This has proved easy to do, and very reliable for operation.
-Kevin
Living the dream.
What IronRooster said above.
I use NMRA WEIGHT RULE RP-20.1 and it works. But some of my Gondolas have real scrap loads and can get heavier then NMRA RP-20.1. I have track with curves, lighter then NMRA RP-20.1 cars can pull in on the curve if not on the end of train. If a train is heavy going up grade...add more power.
Depending on your layout size, how your track is laid down, track work (straight-curve-ascending-descending grades), speed and length of train you normaly run, you could adjust car weight. But why do that, NMRA RP-20.1 works, start with those numbers.
Now when I get a brand new car I weigh it just to see and just put it on the layout and run it. It's usely close enough to not cause trouble.
There is nothing magic or sacred about the NMRA weight standards. What's important is having standards for weight that are practical, reasonable and consistent. The advantage of NMRA standards is that they are all those things AND make stuff interoperable between layouts (and give you hope that a car out of the box is the proper weight without having to do more).
Since empty flatcars and gondolas are so often underweight in spite of our best efforts, it is up to the yardmaster if any to keep that in mind when long trains are assembled. Just like the prototype by the way.
Dave Nelson
IRONROOSTER NVSRR The nmra car weights question occurred to me. Now i might have missed this. Are those wieght standards for loaded or empty cars?Seams to me they are empty weight especially flatcars and such. That's total weight with no distinction between loaded/unloaded. The weight presumbably yields optimum performance trading off between rollability vs drag on the locomotive. Several people over the years have argued for less weight, usually so more cars can be pulled - especially up grades. Others have argued for more weight to help the cars stay on the track or for more realistic coupling/uncoupling performance. Personally, I have found that weighting my cars (and loads if any) to the recommendation works very well. Paul
Count me among those who believe in more weight. Somebody here suggested a standard for HO of one ounce for every ten scale feet of car. That's slightly heavier than the NMRA standard and has worked well for me. It's also easy to remember. I typically run 15-20 car freight trains and most of my locos can pull those up my 1.5% ruling grade. The ones that can't (mostly Bachmann steamers) give me a reason to use helper service.
Most of my rolling stock is somewhat over the NMRA recommendations, but afer upgrading some Rivarossi passenger cars with revised windows, simple scratchbuilt interiors, and lots of external detail, I weighted them to about 15 or 16oz. apiece.
They rolled like true heavyweights, no wigglety-jigglety through turnouts...simply beautifully ponderous motion.
However, it didn't take too many scale miles of service before the soft plastic of the Rivarossi sideframes began to wear, to the point that if a car was picked-up at the end of its run (to be returned to its box until next needed) some of the Kadee wheelsets would be left on the track.I'm gradually collecting some of Walthers nicely-done passenger trucks, and hope to eventually re-truck the Rivarossi cars and re-install the weights.
Most of the cars are currently around 8 or 9oz.
Wayne
I stay pretty close to NMRA weight guidelines, and I prefer metal trucks and metal wheelsets to get as much weight down low as possible.
These cars weigh 4.3 oz and are equiped with Kadee sprung trucks and Intermountain wheel sets. I have no propblems with trains in the 70-100 car range.
Sheldon
With most standard gauge locos, esepcially where you can lash-up several diesels together, there's rarely a lack of power to move even more heavily weighted cars.
It's different in narrowgauge. The locos are proportionately smaller, thus less mass, smaller motors, etc. Operations are mostly steam, so helpers are usually only appropriate on the steepest grade and doubling/MU operation is relatively rare. One loco has to do the work, usually.
Grades tend to be steeper, adding to the challenge. Fortunately, short trains usually work OK, so that is a positive when it comes to getting tonnage moved.
The first RailLine 3000-series boxcar kit I built I weighted to NMRA standard and I quickly found out that was a mistake. It's still the heaviest boxcar on the roster. Turns out that most NGers underweight their rolling stock to facilitate having long enough trains to be realistic. You'll find if you weigh most Blackstone RTR HOn3 that it tends to be underweight.
As Sheldon and others mention, what's really critical is consistency and getting what weight you do have low. For wood kits, that usually means using brass trucks and things come out about right.
Mike Lehman
Urbana, IL
ATLANTIC CENTRAL I stay pretty close to NMRA weight guidelines, and I prefer metal trucks and metal wheelsets to get as much weight down low as possible. These cars weigh 4.3 oz and are equiped with Kadee sprung trucks and Intermountain wheel sets. I have no propblems with trains in the 70-100 car range. Sheldon
Trains of that length will work in N scale. I designed my layout with 25-30 car freight trains in mind but I found trains that long would dwarf the layout. They would extend from on town to the other. 15 cars is more typical of what I run now and no more than 20. I've seen HO trains at train shows with a very large modular layout set up. 50 car freights and 15 car passenger trains. It's very impressive looking but too much for my relatively large basement layout.
NVSRRAre those wieght standards for loaded or empty cars?
i believe the goal of the NMRA recommendation is avoid stringlining and improve rolling.
At least on the prototype according to Armstrong, full cars have less resistance/ton than empty cars.
greg - Philadelphia & Reading / Reading
The NMRA recommendations work quite well, but they are not a panacea for pourly laid trackage, non-"free rolling" railcars, or "not so good" layout conditions.
That said, keep in mind that they are "recommendations" and not "rules".
ENJOY !
Mobilman44
Living in southeast Texas, formerly modeling the "postwar" Santa Fe and Illinois Central
John-NYBW ATLANTIC CENTRAL I stay pretty close to NMRA weight guidelines, and I prefer metal trucks and metal wheelsets to get as much weight down low as possible. These cars weigh 4.3 oz and are equiped with Kadee sprung trucks and Intermountain wheel sets. I have no propblems with trains in the 70-100 car range. Sheldon Trains of that length will work in N scale. I designed my layout with 25-30 car freight trains in mind but I found trains that long would dwarf the layout. They would extend from on town to the other. 15 cars is more typical of what I run now and no more than 20. I've seen HO trains at train shows with a very large modular layout set up. 50 car freights and 15 car passenger trains. It's very impressive looking but too much for my relatively large basement layout.
My last layout, which filled a 1000 sq ft room above my detached garage, was designed for 30-40 car trains, but could handle bigger trains if desired.
My new layout, in a 1600 sq ft space, is being designed for 40-50 car trains and I don't feel that those trains lengths dwarf the layout at all.
But is does have a lot to do with your layout goals and approach. I don't try to model two "destinations", one at each end of the layout, or lots of different "towns" along the line.
There is lots of hidden staging and the trains "pass thru" a series of scenes that represent a single small city, a sub division terminal, and the few miles of trackage on either side of it.
I don't run lots of 100 cars trains, I was simply commenting that properly weighted cars function effectively with trains that long, which I do occasionally.
For me, modeling 1954, a 15 car train is a "local", not a mainline train for my double track class I operation.
Quick math says scaling the weight of a loaded car at 200000lbs would be about 2200lbs in scale. Tad bit heavy. Need some MRC power packs from the early 90s for that ( remember the add with all the ho locos pulling a prototype tank car?).
But what occurred to me is what somebody said. The plastic trucks of the time couldnt handle to much weight or they would wear fast. The practice as design probably accounted for weaker plastic so just enouugh weight was there for tracking but not enough to over wear parts or bend plastic. Todays designs and plastics canbetter handle the wear. A more prototypical balance of weight wouldnt hurt. Like a 60' flatcar shouldnt be the same weight as a 60' box. the box should weight an ounce or two more. Would have to base that on weight ratios of the prototypes. With the starting weight being the nmra standard
i run a regional ooeration with the layout designed for 10 to 15 car length trains. With a ruling grade of 3.81%. And that is on a curve. Dont usually have a string line issue unless it is for the same reason the prototypes do.
Wolfie
NVSRRQuick math says scaling the weight of a loaded car at 200000lbs would be about 2200lbs in scale.
Well, if your going to do that you need to divide by 87 to the 3rd power to account for the 3 dimensions. That will give a result of about 5 ounces.
First Paul is right, scale weight is a cube equation, second, physics does no scale down in a linear equation, so the effects of momentum and gravity are different from real life.
The goal of the NMRA Recommendations is consistant weight based on proportion of length, so while it may not be prototypical, to make our models operate best, all 40' cars should weigh close to the same, empty or loaded, box car or flat car, etc.
Longer cars will exhibit more lateral forces on our sharp curves, requiring more weight for stable operation.
mlehman...As Sheldon and others mention, what's really critical is consistency and getting what weight you do have low....
While I sorta agree with placing the weight low (it's probably the easiest to install) unless you're trains are run at high speeds, especially around curves, it doesn't matter all that much where the weight is placed. Those 15/16oz. passenger cars, to which I referred, had the majority of their weight in the clerestory of the roof....otherwise, there'd be no place to add seating or passengers (the latter still lacking in most of mine). They tracked just fine and I never experienced a rollover of any of them.
This combine, built from a shortened Rivarossi diner...
...has most of its weight in the clerestory...
Most of the de-weighted passenger cars have the weights hidden, as shown here...
...and here, as in this Model Die Casting "Palace" combine....
My diesel-electric doodlebug, The Bee, built from a much-modified Rivarossi combine....
...has the weight in the clerestory, much the same as the formerly-too-heavy passenger cars....
....and the front end, part of the frame from an Athearn F-unit, along with the motor, contributes some added weight, too...
I have, as a test, run The Bee at unprototypical speeds (probably not top speed, though) and it has not rolled-over. It weighs 20oz., and is a pretty-decent puller, although the most I would run behind it would be a couple of trailer coaches and/or a freight car or two.
I built eight of these modified Athearn boxcars....
....and placed the weights upright at the cars' ends....
They're not glued in-place, but rather "trapped" in place by the Evergreen strip material. This location was necessary because the cars' floors are from Central Valley stock cars, and have no integral weight to contribute strength to the floor.I say place the weight where it fits, and don't worry about it.
doctorwayneI say place the weight where it fits, and don't worry about it. Wayne
Wayne,
For standard gauge, that's probably not critical. But I was referring to narrowgauge, where it does make a difference. Top heavy narrowgauge cars tend to not track as well. Everything is rather light anyway, so the higher mass tends to cause issue on grades and curves.
mlehman...But I was referring to narrowgauge, where it does make a difference. Top heavy narrowgauge cars tend to not track as well. Everything is rather light anyway, so the higher mass tends to cause issue on grades and curves.
Yeah, I can understand that, Mike. The narrower stance would definitely have some trouble with top-heavy cars.
doctorwayneYeah, I can understand that, Mike. The narrower stance would definitely have some trouble with top-heavy cars. Wayne
Yes, a somewhat different geometry than with the proportions of the standard gauge car vs 4' 8.5" gauge. More of the carbody ends up as overhang. Typically, this is aggravated by marginal bolster design on many HOn3 models. Often, just a thick plank of wood comprises the bolster. Blackstone does a really good job on theirs, but that's the exception. The kingpin is usually a screw and its fit is often a bit loose and sloppy, depending on the truck, so it further contributes to less than optimal operation. Some of this can be fixed. If you order a pair of Blackstone passenger trucks, they come with one of their formed bolsters IIRC. Not always a solution for an already built model, but a little effort to improve this helps things.