Model Railroading > Can of worms - car weight

Here I go... opening a can of worms. The NMRA has RP-20.1, which is the Recommended Practice for determining what would be the optimum wieght for rolling stock. I know more modelers that add weight than don't add weight. I think the NMRA should change the Recommended Practice to a Standard. I know the NMRA can not make the manufacturers following their Standards, but it could improve what comes out of the box. So what are your thoughts about car weights? Would you like to see manufacturers produce cars that meet RP-20.1? Any negatives to changing the RP to a standard?

Michael Mickens
Placerville, CA
 

I have just shy of 2,000 cars.  I have never once added additional weight to anything, and have never really had an issue. I think this is another thing people spend way too much time thinking about.   

NMRA is an antiquated organization as it is, but thats a different topic.  

Never added weight to any car.

Have only had to add weight to a handful of more than 300 cars on my roster. It's never an issue unless something derails for an unknown reason. I thenalways check the wheels and gauge first, which eliminates 99 percent of derailment problems. Only in those very rare occasions where that doesn't solve the problem do I think about adding weight.

Art House

Down at the La Mesa club is not just about the proper weight, but the location. They have a tool that measures the pitch the car will balance at. I forget the numbers, but basically, the lower the weight. the better overall performance of the car. I'm sure others can add more details. 

Mike ONeill
Parker, CO

That's one can of worms I prefer not to open!

I've always wondered if the weight standards apply to Gondolas and flat cars?  Should they be NMRA weight out of the box?  With that said I've had an issue with a couple of switches and weighing the car down by gluing pennies inside helped me.

I have removable visible loads of lumber, steel, and construction equipment that is added and removed as the cars move between shippers and customers.
Thus the same cars run quite a bit heavier in one direction than another, always without incident.
If a car does not have any weight (e.g. a resin kit) I will add some, and maybe use metal trucks, but I don't worry about the NMRA....
Unless I want to run it on the local club, which insists on following the NMRA quite precisely.  
It's complicated, eh?

I've got some nice metal scrap loads made by a guy in the northern Virginia area which are quite heavy.  I wonder if after a lot of running, the trucks will get worn where the needle axles ride with that much weight!

I think this RP is very generic as it depends on the operation and style of the railroad the car is run on....some people run very long trains and may have helpers, steep grades, etc.  So your answer may vary greatly.  I think this sort of question sounds very much like the classic auto oil change interval (3000 miles? 5000 miles? 10000 miles? per the manufacturer? synthetic oil?) I have built and torn down several smaller railroads due to moving, but whenever I had a derailment, my first focus was on the trackwork and then the rolling stock (gauge, couplers).

As you said, because of the wide range of answers, as well as the wide range of operating environments, is why this is an RP versus standard 

-Sean

And when was the last time the "Recommended Practice" was updated? Things have changed over the years.

I think you folks are missing the point. Much of the weight recommendation has to do with weight per inch so that the cars are of uniform weight by length to help with train handling. Therefore, there isn't any need to update the standard.

Victor Baird



Edited 3 time(s). Last edit at 03/22/23 13:06 by wabash2800.

wabash2800 Wrote:
-------------------------------------------------------
> I think you folks are missing the point. Much of
> the weight recommendation has to do with weight
> per inch so that the cars are of uniform weight by
> length to help with train handling. Therefore,
> there isn't any need to update the standard.
>
> Victor Baird

Agreed!

The newer models are pretty close generally. I like models to be on the heavier side, I think the run smoother and back up better. That being said I won't add weight unless there is a operation problem. I have some older Kato covered hoppers and a few flat cars that won't see the layout anytime soon because if you take your finger of them, they float away....Projects for another day.

My point was that the RP was written back in the days of X2F couplers and such. Current equipment fitted with the now standard knuckle couplers and modern trucks tends to work much better.
So maybe a revisit to update the data with current data might be in order?

While things have changed indeed, better rolling wheels and tighter tolerances on coupler boxes, properly weighted cars play a larger role in good train performace than you may realize. Lighter cars are more apt to pick switches and ride up on imperfections in the track than heavier cars. I've seen many things over the decades at dozens of clubs, and I've fixed many problem cars by adding weight to them. Light cars also hate helixes. Better have the trucks tightened up to minimum looseness so the in train lateral forces are put to the wheel flanges and not trying to pull the car off it's center of gravity.

Ted Curphey
Ontario, OR

Another issue that hasn't been mentioned.  Heavier cars are less prone to shimmying as they roll down the track.  This is a pet peeve of mine, I hate to see cars vibrate like that.  So give me more weight, placed as low on the car as possible, and metal wheels, too.

 If somebody could model realistic, slow speed back and forth movement, I would really like that.

Well, Has anyone ever had a car derail because it was to heavy? (No)
Have you ever had a car derail because it was to light?   (Yes) 
I have cars that weigh 1.5 NMRA weight & cars that have no weight of any type added. My 16 car auto rack train runs very well. 
My 30 car roadrailer only has the first 3 Roadrailers with weight (5.3 oz) & no weight in the rest except for frame, Body & metal wheels.
I think it depends on how we run our trains. if you like long trains have the first part weight more then the rear.

Tim
Hanesworth