The original post was not about couplers' heights. That's a subject for another time. Most know that manufacturers are somewhat compliant with car weights. Taking a manufacturer's "word" for a car weight is not a good policy. Checking each car and adjusting its weight as appropriate (your standard or the NMRA's) is a policy to follow.
This subject comes up every so often. Several yrs ago a search was made to find out how the NMRA arrived at their standards. Nothing was found. Not a clue. One criterion for proper weight is how the cars track the rails and how much tracking jitter there is when cars cross turnouts. I ave both medium size N-scale and HO layouts. Using NMRA standards for HO weight, Ive found that most cars track well when the track and turnouts are installed properly. This is not the case with the n-scale weight formula. As far as I know, the weight formulas where established more than 50 yrs ago...before n-scale had much of a presence. The formula W = 0.5 + 0.15*L is wrong with regard to the slope of the curve (0.15). N-scalers will get much better tracking performance (in line with HO) if they raise the slope to 0.25 - 0.30. The formula becomes: W = 0.5 + 0.25*L (or anything between 0.25 and 0.30). In the range of n-scale lengths betweem 4 and 6 inches, weight is increased by roughly 35%. I dont think the HO formula needs alteration, except maybe a change of the slope from 0.5 to perhaps 0.6: W(HO) = 1.0 + 0.6*L.
PM Railfan First off, Railfans never get exhausted from talking about trains. Real trains use empty and loaded cars mixed thru out the train. If your careful on the throttle and your track is good.... you can do the same. To including - backing up (pushing cars). Talgo trucks? IMO i dont recommend them. Kadee equipped or not. However - they do have their purposes. I think adding weight to your cars uniformly is a con, not a pro. Cars are distinctive in appearance, and handling. Weighting them should be too. I have noticed Kadees perform much better than X2F (horn-hook) couplers for pushing operations (any operation actually). So your off to a good start. Ideal placement of weight would be in the original manufacturers compartment for the weight. Adding weight between the frame rails under the model is a good place and a very low center of gravity. PMR
First off, Railfans never get exhausted from talking about trains.
Real trains use empty and loaded cars mixed thru out the train. If your careful on the throttle and your track is good.... you can do the same. To including - backing up (pushing cars).
Talgo trucks? IMO i dont recommend them. Kadee equipped or not. However - they do have their purposes.
I think adding weight to your cars uniformly is a con, not a pro. Cars are distinctive in appearance, and handling. Weighting them should be too.
I have noticed Kadees perform much better than X2F (horn-hook) couplers for pushing operations (any operation actually). So your off to a good start.
Ideal placement of weight would be in the original manufacturers compartment for the weight. Adding weight between the frame rails under the model is a good place and a very low center of gravity.
PMR
I can just see all the derailments coming with 1 oz "empty cars" mixed in with 3.5 oz "loaded cars" in my typical 35-45 car trains.
Physics does not scale.
Most of my equipment is at or just under NMRA RP20 recommendations.
The first and primary way I ad weight is with sprung equalized metal trucks with metal wheelsets on nearly all my freight equipment.
Most are Kadee trucks refitted with Intermountain wheel sets.
Its been working well pulling long trains for a lot of years. I have pulled 100 cars trains without any problems.
Sheldon
Thanks guys for your responses. I understand the need for boosting the weight on open cars, but what are the pros and cons for adding extra weights so that all cars are uniform in weight? I don't see the negatives = other than possible motor damage.
Also, we haven't touched on the ideal placement for the weights - mid car or over the trucks? How do you handle the weight issue on mixed trains - a 40' box at the front of a few heavy weight passenger cars?
And, speaking of 'pushing' - I had the bright idea of putting talgos on some freight cars to get into tight industrial areas. Am I the only one who learned a vital operation lesson? Again, everything is Kadee equipt.
That should exhaust the topic for a while
Dorassoc1So, now that I've antagonized half the audience, what do you folks do about the weight issue?
Our club requires NMRA weight...except it's an older NMRA standard. We have a length gauge that shows the required weight for a given length, divided into 5-scale-foot increments. The car has to be within 5 feet of its weight. Most cars out-of-the-box with metal axles and couplers are in range, including old Athearn BB.
This makes it *very* difficult to do removable loads, as the car weight cannot change too much with and without. One member has proposed an alternate standard for, say flat cars, which don't look very realistic unloaded.
We have steep grades and long trains, and having the right weight is necessary to avoid stringlining (falling into the center of the curve) on the sharpest loop. Also helps with slack run-ins which are an issue on 40+ car trains. Too heavy can be an issue too -- a friend just gifted me a brass passenger car that he's had a heck of a time getting running. Seems the light trucks get shoved off the track too easily.
We do allow unit trains with non-standard weight. I run two ultralight cars (Bachmann tourist cars) but only on a 3-car train. Mostly we find that if we stick to proper weight, everything runs nicely together. We inspect every car that has a derailment, and being over/underweight is a common problem. As is out-of-gauge axles and wheels with big-time crud build-up.
Aaron
Some of my rolling stock is 60 years old, and some is very recent. Some are kits, others RTR. Everything now has Kadees, but I've replaced a lot of horn-hooks over the years, including Talgos. My wheelsets are all metal now, but most used to be plastic.
When I buy a car and put it on my layout, it's like adopting a cat. It has a forever home, and it's my responsibility to care for it. I adjust the coupler height and I take care of the weight.
I've only needed to add weight a few times, generally to off-brand flat cars without loads. I've had to remove car weights when adding Chooch resin scrap loads to gondolas. Those loads are heavy!
It takes an iron man to play with a toy iron horse.
I just have to throw myself into the mix here.
Have been modeling HO scale for about 40 years. In all of the cars I have purchased over that time, I have yet to add weight to a single car. This includes the fleet of about 190 cars that I currently have on my 14' x 21' layout. If I buy a used car with weights, I remove them. Mind you, I don't have any grades, and was meticulous in laying the track work. Yes, I can slowly back up a typical mainline train of about 20-30 cars and 2 engines for several feet, if I need to. Perhaps, if I tried to back up one of those trains all the way around the layout, I might have a derailment. A derailment on my layout is caused by me not setting a switch correctly, never from a 'light' car when traveling in the normal forward direction.
Here's where it gets messy. :-) I totally get that you would want to weight cars if you need to back several of them up a grade. But in my opinion, there is way too much paper and ink wasted on the pages of MR worrying about NMRA RP 20.1. I personally wish they (editors) would hold manufacturers accountable for the >> coupler heights << on cars. How many of us have a hodgepodge of KD couplers, red and blue washers, and various heights of wheel sets on hand because of this problem? How many prototypes would be in business today if their couplers didn't mate correctly with a standard height of other cars? I have not purchased (that I recall) any of today's $30-and-up RTR models, but would sure hope they don't have this issue. Seeing material on the pages of MR of a model adhering to a NMRA RP regarding coupler height - now that might get me excited about an NMRA membership. :-)
Cheers!
Mark VW
BN7150Can you understand this comment
Yes, your points are well made.
Cheers, the Bear.
"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."
I have some cars that are at the recommended weight, but generally, I adjust the weight until the car performs best.
All this business about spread sheets and so forth. For the past 30 years or so I don't seem to remember ever having a problem measuring the car length, multiplying by 1/2, and adding 1.
I learned about RP20.1 25 years ago and tried it on my models, and there was no derailment. I expected that this is a rule of thumb derived from Athearn's box cars, and that the car length factor would be related to the radius of the curve. In the model, the radius of the curve is too small and the speed of passing the curve is too fast. The model trucks are not equipped with springs, or even if they are, they are not functioning properly. The manager of the model railroad does not have the necessary knowledge and does not carry out regular inspections and repairs. Therefore, standards and recommendations must be largely swayed to the safety side.
There are several derailments that are unrelated to the turnout. There are flange-rising, flange-sliding-up, jumping, wheel-load-missing, excessive lateral pressure, upright wear of flanges, irregular track, abnormal increase in friction coefficient, and excessive attack angle. In the model, increasing the weight is effective in all of these cases.
Considering only derailment, heavier weight is advantageous. Of course, it is disadvantageous for traction.
If the position of the weight is lowered, it is difficult for the wheel load to miss. Moreover, if the position is set to the center of the body, the influence of inertial force on the wheels can be reduced. Of course, you need to pay particular attention to the left-right balance.
Here are some cases where I think it's better to make it heavier than RP20.1. When the truck does not easily rock from side to side and back and forth. When making a long train with a car equipped with Talgo trucks. When adopting short shank or overset shank for the coupler. When a long car with a swing draft gear. When the distance between the truck centers is extremely short, such as in a beer can tank car. When the distance between coupling surfaces is extremely long compared to the distance between fixed axles such as non-powered steam locomotives, or when the distance between fixed axles is long such as 6-wheel trucks and centipede tenders.Many causes are buckling due to coupler force.
Can you understand this comment. :PKotaro Kuriu, Kyoto, Japan
I use cars as I get them. If they act up, I check gauge, check coupler pins, and add weight, in that order. (Weight temporarily.) If they still don't play nice, I reduce weight. If still no go, I check the truck frames. If still no go, they become shelf queens until I can practice some skills on them, like air brushing or weathering with powders.
You basicly have to deside which way to go as far as weight. There are those that like low weight so they can run longer trains, for awhile I overweighted mine because of the action on sprung trucks, now I mix weights so when switching you need to deside where a car is in the train, a bunch of lights and then a heavy at the end is a derailment waiting to happen on some curves.
For those of you who have Microsoft Excel here is an easy to make a weight calculator... (the example is for HO scale)
Open Excel and create a new spreadsheet. (the default open)
Use cell "A1" to enter our "real train weight" ie: a boxcar weighing 45000lbs empty.
Use cell "B1" for our answer in 'ounces' of what our HO scale car should weigh.
Select cell "B1" and enter this formula.... (only type exactly whats between the quotes)
"=SUM((((A1*16)/87.1)/87.1)/87.1)"
Now, whatever amount of weight you put in cell A1 will be translated to ounces of HO scale weight in cell B1. Save your file so you have it when you need it. Done!
You may need to 'format the cells' to display your numbers correctly (default format works, but isnt pretty). That can be done by selecting the cell you wish to alter - in this case cells A1 and B1. Right click on either one and follow the prompts that lead you to your personal choices of how to display your info.
Normal selections would be for A1 to take out the decimal and add the comma. For B1 you may want to only display a decimal of two places instead of the default 4.
For other scales like Z or even G, change the formula above everywhere you see an "87.1" to the scales proportion that you model.
You can also change the cells you want to use by changing A1 or B1 to some other cell. Just make sure the input weight is reflected by exact cell number in your formula.
Have fun!
Dorassoc1 And I know there is nothing more awe inspiring than seeing a little 0-4-0 pulling 35 freight cars up a 3% grade...So, now that I've antagonized half the audience,...
Read here:
https://www.nmra.org/beginner/weight
Mike.
My You Tube
AFAIK, the NMRA completed that RP back in the day through trial and error. However, back then the hobby was much different. Trackwork was more questionable and tight curves were more acceptable. Herky-jerky locos were more common and electrical continuity was more intermittant. Performance of model trains overall was not nearly as good as today. The weight of the cars recommended by the NMRA is a little heavy compared to what we can actually get away with. The real trick is not to have any really heavy cars or any really light cars mixed with each other on the same train.I've built old Athearn all-metal kits (they were re-released by Bowser) and they made me appreciate the quality of today's models even more. They did turn into a decent kit, but man, the work involved getting them together.As for prototype weight, just remember that to reduce things to HO scale weight you have to divide it by the cube. After all, weight is based on three dimensions, not just one. So say you have a 45,000 lb. (empty) 40' boxcar in real life. In HO scale, you'd have to divide 45,000 lbs. by 87.1 three times (length, width and height), and so you'd get 1.08 oz. Put 50 tons in it, and it'd add 2.42 oz. Total: 3.5 oz., which is actually pretty close to the NMRA RP of 4 oz.
My train cars are all weighted, but not to NMRA recommended practice.
Anything 40 feet and below is 4 ounces.
41-50 feet is 5 ounces.
60 feet and up is six ounces.
-Kevin
Living the dream.
I know the proper weight for my rolling stock (1 ounce + 1/2 ounce per inch of the length of the car - at least according to the NMRA RP 20.1. How did they come up with that? And I know how busy the MR reviewers are if the car is 1/2 ounce too light. And I know there is nothing more awe inspiring than seeing a little 0-4-0 pulling 35 freight cars up a 3% grade. But frankly, I prefer a more realistic situation where one of my 44-tonners struggles with 4 - 5 cars - similar to what occurs in real life. So I typically add to the recommended weight, which,as an added bonus helps when pushing a car into a siding. Open cars, where I can't add additional weight under the car, all have loads.
So, now that I've antagonized half the audience, what do you folks do about the weight issue? What is the NMRA RP based on? Anyone remember when MDC cars were real metal, as were Athern's?
I'm eagerly 'awaiting' your responses.