Super Weighting

Thanks Brian;

That is an article I would have skipped and missed out on the weighting portion. Bill has a entertaining writing style as well so I won’t make that mistake again. Since joining this forum my cars have been slowly getting heavier. These are On30 so there is no real recommended practice but I find that a 30’ car (7-1/2”) can be weighted to 2 oz per in or nearly one pound on the rails. The size of my cars are similar to HO, and even share the same track gage, but are considerably wider and taller so the extra weight really adds a lot to the visible motion to a train as well as a real challenge to my little tea kettles!

Nice!

At least somebody read my article

I learned about super-weighting from following Mike Confalones writing and videos on MRH's various platforms. It truly does improve the handling of the cars, preventing them from bumping around like balloons as you handle them in trains.

I read your article too, Bill

I also weight my cars to about the same level Bill does, Also inspired by Mike Confalone's practices.

Just read the article - Well Done!

As I model in N scale, I'm wondering how I would translate that 7 oz. to my little railroad.

N scale superweight

This is just me thinking out loud... I am not authoritative in pretty much any way. 

Well, the NMRA weight for that car would be 4oz in HO, and in N scale, figuring on a car length of about 3.2 inches, it would be just about 1oz. That's the NMRA numbers, more or less. See RP-20.1 for more info:  https://nmra.org/sites/default/files/standards/sandrp/pdf/rp-20.1.pdf .  So figure a ratio of 1:4 between N and HO scales, and 7oz turns into 1 3/4 oz. 

Try it and see how it works. 

Try it and see how it works

I would second Don’s thoughts on this and wonder if anyone is up for testing weights using modern wheels, longer cars, and engines with more efficient motors (and no traction tires). Like Jeff said “Try it and see” really points out one other factor of personal preference. 

My cars are weighted so that some engines can not physically pull too many cars. Even an engine like my Bachmann 4-4-0 has no trouble with a half dozen passenger cars - stock. Add some weight and it has to pull one car at a time to get the train rolling (one nice thing about coupler slack) but cannot go up a 3% grade without leaving some behind. Doubling a hill is a built in operational challenge. Even my Shay will start bucking with too many cars but has traction on it’s side. 

Weight scaled down

I add 80 cents to each car,

Don't forget inertia

Decades ago I had a string of NWSL (model name forgotten) boxcars with flywheels. While not real heavyweights, having several on a train and trying "hot rod" starts would likely cause a Kadee knuckle yanked off.

Jose.

I can only hope to achieve

Something to consider

Let’s consider that mass does not scale. A model of a 50’, 50 ton boxcar will carry the same weight per square inch as our model. The model is 1:87 times the actual size so (roughly in inches) 108”x96”x600” is 6,220,800 cubic inches or 0.016 lb/cu inch (100,000 / 6,220,800). The model is 1/87 the actual size or (again roughly) 1.5x2x7=21 cu in x 0.016 lb / cu in or .336 lb (5.4 oz or a little over 3/4 oz per inch). 

My little narrow gage 1:48 24’ boxcar could only carry about 10 tons. It was 7’x7’x24’ or 2,032,128 cu inches. It scales roughly 2x2x6=24 cu inches. 20,000 lbs / 2,032,128 cu in = 0.0098 lbs / cu in x 24 = .24 lbs or 3.78 oz.

Even though this looks to align with recommended practice, this doesn’t sit well with me as I know that mass and force are linked to determine inertia. My models may scale the same as the prototype but don’t act the same way. In fact, at these weights it would imply that  our engines are either too strong or the cars too light. Seems like it is easier to just add weight to the cars. I like to limit the engine strength of a steam loco to two cars per axle on the level. Every percent grade reduces that by half. A 4-4-0 shouldn’t be able to pull more than two cars up a two percent grade.

Anybody care to figure out motive power to scale?

I started overweighting my cars...

...about 10 years ago after operating a layout with heavy cars, they run much nicer and couple much better with out having to "Bang" cars together.

My completely arbitrary and non-scientific decision was to take the NMRA formula and add 2 ounces. seems to work OK. I think it is less of a weight issue as a consistent weighting. No goo having a pair 8oz car s if the one in betweenis 2oz!

Neil, you are correct. Weight

Neil, you are correct. Weight does not scale. The really frustrating part would be to determine weights by volume of different substances. I tried this on here with others having a spirited debate. I suspect that you already came to the same conclusion as I did the way to find the answer to your particular situation is to experiment.

In my case I did that adding weight till I reached a given performance point for my freight cars. I was not setting out to limit the performance of my locomotives. My goal was to have no cars that "vibrated" down the tracks while rolling along. I wanted to run prototype length trains with out string lining on curves. I wanted to be able to back up a train and put them into the yard. When backing all the cars needed to stay on the track.

Fortunately for me my first cars were open top hoppers in different lengths. I was able to add steel nuts till I got to a point that trains of 100 cars or better could back up with out issue. My starting point was to get to 160 car trains that the C&O ran across the state of OHIO.

My experiment showed that I could run 187 car trains with no derailments forward around the layout up and down grades very reliably. I stopped at that point as I ran out of freight cars. The added weight was between 1 and 2 oz over the NMRA standard for HO cars.

One other thing I found was trains that were shorter, typically under 40 cars worked fine at the standard weights in HO scale on our club layout. I suspect sharper curves and steeper grades would shorten this length of train a bit.

I was also quite surprised regarding pulling power of the trains. A test regarding the atlas Trainmaster locomotives regarding pulling power in MR magazine showed them to be capable of pulling 60 cars on straight and level track. They also seem to be able to pull this same amount or better up curving grades that peak over 2%. I suspect that tuning the rolling stock also increases the pulling power, at least in HO scale. I also tuned the locomotives.

Because of my initial impressions with improved performance after tuning my locomotives and freight cars. The first thing I do is disassemble all equipment and get it to my standards of rolling qualities and weight with rolling stock, and clean and lube all locomotives and make sure all portions are assembled properly. One of the guys teases me about this all the time.

I was quite interested to find out that the recommended practices were developed by the early 60s in another post. I suspect that the guys doing it did not have the plastic trucks that we now have. I am also wondering if we now have better wheels also. Since we now have 5 decades of product development since the time of the recommended practices I think the best way to find things that work in a given situation is to experiment, starting with the recommended practices and going from there.

The other thing that seems to be very beneficial in modern times is the sharing of info over the web. By finding someone with similar goals and operating parameters it is possible to greatly shorten the experiment and testing phase to find something that works for ones situation. I know this saved me from lots of dead ends when developing my standards for performance.

Thanks

Thanks for the tips on trying over-weighting for N scale. I'll do some experimenting - this is a facinating topic for sure.

NWSL "Drifter"

Pipopak,

Those NWSL cars you referred to were called the "Drifter" - I still have one in my collection of stuff.  They have a flywheel that is coupled to one axle with a rubber band type thing.  The idea was that you could shove them and they would "drift" for quite a while.  Which they did, providing you had good wheels/axles on the car.

I actually knew the fellow that developed this product for NWSL - his hame was Clark Stumpfke (sp?).  He lived not far from the old North End Hobbies on Roosevelt Avenue in Seattle, and he built a working hump yard for his layout in his basement.  Quite a character!

Al Carter

A couple thoughts

One thing that comes to mind immediately is that plastic Kadee knockoffs probably won't handle the forces generated by the extra mass, at least not for long. I fully understand that most if not all of us change our our couplers to Kadee at the first possible opportunity, but still something to keep in mind.

The second thing is that even just properly weighted cars can erode their journals until the axles wear through, especially with plastic/Delrin trucks and metal axle wheelsets. IIRC, Tony Koester once posted a story in his "Trains of Thought" column about a coal train that suddenly wasn't running right and was making horrendous noises. Turned out the axles in some of his cars had worn through the top of the truck journals and the cars were now dragging down the track. Again, IIRC, his advice was to institute a regular maintenance check and make sure the journals didn't have an unacceptable amount of wear, and to never store cars upright on their wheels, because over time, just the weight pressing the plastic trucks down on the metal axles is enough to cause journal deformation and erosion. That last bit isn't very helpful for those of use who leave rolling stock on the layout between sessions, I know, but something to file away for consideration nonetheless.

Mike in CO

Forces on couplers

I change out all my couplers to Kadee #5 or other metal shank (short/long shank or offset head) as needed. I had used some of the 20 series, the insulated couplers with the delrin/plastic shanks, years ago because they were cheaper for a student budget. I found that on long trains of 60-70 cars the pulling weight would cause the coupler shanks to flex (one coupler head flexes up and the other flexes down) until they eventually uncoupled on bad track.  Of course, as soon as you stopped and took the weight off the couplers, they immediately returned to normal so you couldn't tell anything was wrong.

These days, I'll use the "rubber shank" couplers only if absolutely needed, and make sure the coupler box is nice and tight to prevent shaft flexing.  Of course, on my current layout, I never run more than 7 cars so it's not a big issue at the moment.

Craig