Determining Car Weight...

[Anonymous]

In determining car weight the NMRA Recommended Practice 20.1 states 1 oz. plus 1/2 oz. per inch
of length. If I have a car 6 1/2" long how much more weight would I need to bring it up to standards? Is there a table or a conversion chart
that says this? I weighed most of my cars and most
came out around 4 1/2oz. Is this correct?
The car cannot be too light or too heavy or it might derail.

[Anonymous]

The formula you cite is correct, although I always round to the closest inch and have not had a problem. In your case the proper weight is as follows:

1 oz + .5 oz (6.5)= 4.25 oz

That is the toal weight of the car. Weigh your car w/o weights added to determine how much weight to add. I use the lead weights that have adhesive attached. They come in either 1/4 or 1/2 ounce increments. I know that other have used pennies and glued them into the car. For flat cars, gondolas, etc. you might want to consider using the flat lead weights.

Hope this helps.

[Anonymous]

If? you wi***o add pennies,
1 penny=.0881834 oz.
9 penny=.79365 oz.
11 is just under an ounce
12 is just over an ounce.

[BRAKIE]

Well,Not to debate over this,here is something you should think about.If all you cars weigh differently then you may be setting yourself up for trouble.Ok,say you have a car that weighs or say 7oz behind a car that weighs 5.(short then long car) this may cause derailments on curves by string lining on long trains.Now,at both clubs I am a member we do not weigh the cars and have had no problems with long trains.As I said this is only something to think on.
A little history of RP20.1 When the NMRA came up with that RP it was badly needed.Some of the kits came with weights,others did not.Some cars was plastic others metal,some wooden kits.Now,do you see the problem of that day and time? Most cars in those days was 36' or 40' very few 50'cars.This does not include pasenger cars.(which by the way had the same problem.)Now,fast forward to todays longer cars,We have 50'-87' cars now if all the different lenghts of car weigh different there maybe problems.Again this is only something to think about.Most cars today weigh about the same.

[BR60103]

The January 2002 issue of the NMRA Bulletin has an article on wighting cars with explanations and lots of photos and charts.
The point about NMRA Recommended Practices is that they make your cars compatible with evryone else's. As long as you are consistent your cars should run together, but the RP was developed with a lot of experimenting and thought.
I think that a little variation is OK, but I wouldn't want to vary more than half an ounce from the RP.

David

[Anonymous]

Adding weight to car will often cure a derailment problem but I've found that good track alignment and and attention coupler swing and back to back wheel set gauge as per the NMRA standard gauge cures most any derailment problem regardless of the weight of the car. In my opinion "lighter is better" I run 20+ car trains on my narrow gauge layout with 3% grades and no problems. If my cars were weighted to NMRA standards I'm limited to about 5 cars. Sometimes..."ya gotta bend the rules". Also if by chance you are using horn hook type couplers convert to Kadees. Horn hooks don't have enough swing and cause deraiments. Hope this helped... Take Care...Vic

[Anonymous]

Vic:

As always, I appreciate your insight and experience. Your points are well taken.

I run a more modern railroad with multiple units. I don't have grades over 2%. All I can say that once I started conforming to the NMRA standard my derailments declined significantly. All of this goes to show that people need to experiment a little bit to see what works best for them.

Jim