Hello All, I’m new to the forum, but a fairly long time model railroader. I have recently kitbashed some n scale gondolas and am trying to get the weighting correct. NMRA standards are for .5 oz plus .15 per inch. When measuring the length, do you round up or down or just split the difference? I cannot find that anywhere or in any archived weighting articles?? Thanks!
Welcome!
I’m in HO scale, and I usually round up.
Mike.
Welcome to the forum![#welcome]
The NMRA weight reference you’re referring to is not a ‘standard’ but a ‘recommended practice’. I usually try to get a 'feel for the car and yes, I do reference the NMRA practice. I always round up…
Here’s a copy…
https://www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-20.1.pdf
Good luck and enjoy!
Neal
One thing I’ve never seen stated with the NMRA recommendation is whether you measure coupler to coupler or the body length.
I use a formula someone suggested several years ago that’s a lot easier to figure. One ounce for every scale foot of body length. It makes for a slightly heavier car but I prefer that anyway.
Shame on me, I guess, but I don’t add weight to any of my rolling stock, freight or passenger. I do, however, add significant weight to the few dummy B-unit locomotives that I own to try to more closely match the weight of the A-units.
Rich
so a 40’ boxcar is nearly 3 pounds?
You’d need depleted uranium to do 89’ TTX flats… [:D]
The NMRA standard is 1 ounce of initial weight plus 1/2 ounce of weight for every 1 inch of body car length. So, a 40’ prototype freight car would measure 5.5 inches in HO scale. Thus, you would add 3.75 ounces of weight.
Rich
Sorry, typo. I meant to say one ounce for every TEN scale feet of body length. A 40 foot boxcar is 4 ounces. That’s slighty higher than the NMRA recommendation which would work out to 3.75 ounces (1 + (.5 X 5.5)). For a 50 foot boxcar, it would be 5 ounces as opposed to 4.5 ounces by NMRA recommendations.
Come on Rich, just having a little fun.
So, a 40’ box car would be 40 oz., or 2.5 lbs., a train of 10 cars would be 25 lbs. [:O]
Now, back to the draw bar pull thead, just how heavy would your HO scale locomotive have to be to pull that?
NOW I know why some modelers don’t use foam, and nail the track to the plywood. [(-D]
Mike.
OOPS! never mind, [(-D] I see John snuck a post in while I typed.
Oh, I knew that, Mike. [(-D]
I just recited the standard for the sake of the less knowledgeable readers than you or I, recognizing our brilliance. [swg]
Rich
This doen’t seem right to me. That would mean a forty ft boxcar would weight 40 ounces. Just a tad heavy
John’s calculation has been debunked in subsequent replies.
Rich
Surely he means one ounce per inch of model car body.
That’s still a tad heavy.
The important thing for the OP is to realize that matching car weights for your specific collection to be run on your layout has advantages.
NMRA standards help modellers weight rolling stock so it will run well when combined with rolling stock owned by others, such as at a club layout.
For your own home layout you just want all of your rolling stock to be somewhat close in proportional weight.
A little added weight helps keep light rolling stock stay in the gauge. Too big a weight difference can lead to problems. Light cars between the locomotive and the end of train can get pulled off track in curves, for example (stringlining, which also happens in prototype. )
Maybe 1 oz per TEN scale feet?
–Randy
1/2 oz per 8.7 scale feet? Plus one ounce for luck…
Whatever works. I just go by the NMRA standards. I already had a test track with a Kadee couple guage at the end - the old metal one with an actual coupler. So I stuck on a label graduated in half an inch incrememnts with the NMRA weights marked instead of inches. Stick a car on, couple it up - look at what the weight should be. Easy peasey.
Many of my cars are heavier than standard though. Especially open hoppers with loads. Try as I might, it never causes a problem. Even putting an underweight long flat car or gon in front of at or over NMRA weight cars - still no stringlining. That’s deliberately trying. If they don’t come off the track under overly rough handling, then running them properly with smooth stops and starts is not going to be a problem.
–Randy
While we’re on the subject, I’m curious as to how modelers add weight to their tank cars which are usually under weight whether RTR or kit built. Some are seriously too light. With some tank cars its easy to get inside the tank and add some weights but with others, especially some RTR, it’s not that easy. I was thinking of drilling a hole in the bottom of the tank, dropping in enough BBs to bring it almost to weight and then pour Gorilla Glue into the hole. I would then plug the hole and turn the car right side up so the BBs and the glue would settle to the bottom. Does anyone have an easier way to do this.
I use a couple of 1 ounce egg sinkers hammered into more of a cylinder shape and glued into the tank body.
-Kevin