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Define "free rolling"

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Posted by steemtrayn on Sunday, May 6, 2018 1:42 PM
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Posted by cefinkjr on Saturday, May 5, 2018 9:53 PM

steemtrayn

To prevent parked cars from rolling away, I place a neodimium magnet under the track. Strong enough to hold the car by the trip pin, but not enough to keep the local from taking it away.

Don't know what "neodimium" is but I may have finally found a use for a set of Button Magnets that have been cluttering my work desk for years.  They are a full half inch in diameter but one was easily trimmed with a razor saw.  It seemed to work nicely after I removed the foam tape backing that made it too thick.

Another of those million or so "why didn't I think of that?" ideas.

Bow

Chuck
Allen, TX

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Posted by cowman on Saturday, May 5, 2018 7:08 PM

I agree, Vasoline does not belong on the axels.  It works fine  on my tubas tuning slides.  Now back to topic.

Somewhere, years ago, there was an article or some other mention of "tuning up your rolliing stock."  I built my "test track" on a 4' pine board.  Under one end is a 1/2" piece  to raise the end.  As I recall, this was lower than the recommended height, but I wanted to be sure.  My Kadee coupler gages are at each end.  I also added a "Snap" turnout to be sure the cars would roll and turn through it freely.

Felt this was a good project for some of the old brass track I had laying around.  The other use is cut to scale 39' lengths (some shorter) for use in maintenance yards or as loads.

Have fun,

Richard

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Posted by steemtrayn on Saturday, May 5, 2018 3:09 PM

To prevent parked cars from rolling away, I place a neodimium magnet under the track. Strong enough to hold the car by the trip pin, but not enough to keep the local from taking it away.

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Posted by gregc on Saturday, May 5, 2018 2:42 PM

when does it matter?

here's a table of the additional force in ounces to pull a number of cars up a grade where each car is assumed to be a 40' car weighted to NMRA recomendations (3.76 oz).  The force in addition to friction to pull 40 40' cars up a 2% grade is just over 3 oz.

The table also indicates the force for a single car up a grade.  If a car barely rolls down a 2% grade, the friction force is ~0.075 oz.    If all 40 car were like this, it means it will take 3 oz of force just to overcome the friction pulling 40 cars on level track and ~6 oz to pull those cars up a 2% grade.

If cars easliy roll down a 0.5 % grade, the friction is < 0.02 oz, and the friction for 40 cars is 0.76 oz (40 * 0.019 oz) and ~3.76 oz is needed to pull those 40 cars up a grade.

I have a brass 0-6-0 that i've measured having a 3 oz pull force.

  3.76 oz,  40 ft,   5.5 in
grade 1 5 10 15 20 25 30 35 40 n 40ft cars 0.25% 0.009 0.05 0.09 0.14 0.19 0.23 0.28 0.33 0.38 0.50% 0.019 0.09 0.19 0.28 0.38 0.47 0.56 0.66 0.75 0.75% 0.028 0.14 0.28 0.42 0.56 0.70 0.85 0.99 1.13 1.00% 0.038 0.19 0.38 0.56 0.75 0.94 1.13 1.32 1.50
1.25% 0.047 0.23 0.47 0.70 0.94 1.17 1.41 1.64 1.88 1.50% 0.056 0.28 0.56 0.85 1.13 1.41 1.69 1.97 2.25 1.75% 0.066 0.33 0.66 0.99 1.32 1.64 1.97 2.30 2.63 2.00% 0.075 0.38 0.75 1.13 1.50 1.88 2.25 2.63 3.01
2.25% 0.085 0.42 0.85 1.27 1.69 2.11 2.54 2.96 3.38 2.50% 0.094 0.47 0.94 1.41 1.88 2.35 2.82 3.29 3.76 2.75% 0.103 0.52 1.03 1.55 2.07 2.58 3.10 3.62 4.13 3.00% 0.113 0.56 1.13 1.69 2.25 2.82 3.38 3.94 4.51
3.25% 0.122 0.61 1.22 1.83 2.44 3.05 3.66 4.27 4.88 3.50% 0.131 0.66 1.31 1.97 2.63 3.29 3.94 4.60 5.26 3.75% 0.141 0.70 1.41 2.11 2.82 3.52 4.23 4.93 5.63 4.00% 0.150 0.75 1.50 2.25 3.00 3.76 4.51 5.26 6.01

 

greg - Philadelphia & Reading / Reading

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Posted by cefinkjr on Saturday, May 5, 2018 2:08 PM

Graham Line
spin a graphite pencil inside the bearing.

Another of the million or so "why didn't I think of that?" ideas.

Bow

Chuck
Allen, TX

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Posted by dknelson on Saturday, May 5, 2018 11:16 AM

Graham Line
spin a graphite pencil inside the bearing.

Kadee has sold powdered graphite for years to "lube" their couplers, and there is also a line of powdered graphite intended for Pinewood Derby cars, but I have used the stuff in trucks (before the truck tuner - and before the truck tuner itself was around I would twirl a small phillips screwdriver). 

This graphite pencil idea offers more control and less mess than the powder.

Dave Nelson 

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Posted by MisterBeasley on Saturday, May 5, 2018 10:23 AM

I built a carfloat terminal a few years ago.

The float itself holds a string of 6 cars on each of the 3 tracks.  I worked very hard to keep everything level, all the way to the back of the layout.  I wanted to be able to pull each string of 6 cars off the float, plus the 3 "idler" flats so the engine didn't have to go on the bridge.  One of the engines is an 0-6-0 tank engine, not much weight or pulling power, but I was able to do it with all metal wheels and cleaned-out trucks.

I learned a couple of things.  First of all, loading and unloading a real car float is not done by pulling an entire string of cars at once.  It is done a half-string at a time to better maintain balance.

Second, don't put a carfloat terminal in the back of the layout like I did, with only a thin, awkward aisle for access.  Uncoupling shoud be reason enough, but there are all sorts of opportunities for minor derailments and other issues.  When I re-build my layout, it will be up front.  Besides, it's a very interesting scene, and it should be up front where people can see it.

It takes an iron man to play with a toy iron horse. 

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Posted by Graham Line on Saturday, May 5, 2018 9:07 AM

Instead of an oil or grease lube, we touch up the axle end cone with a truck tuner, and then spin a graphite pencil inside the bearing.

The truck tuner is the conical cutter like the one now sold by Micro-Mark. Sometimes it just knocks out a little bump or two in the molding, sometimes it will pull out a whole curl of plastic. It doesn't require much pressure -- have seen people try to reshape the bearing seat, make the cone deeper, and then wonder why the wheelsets wobble side to side.

The graphite pencil is solid graphite from the art supply store, with a lacquer coating to keep your hands clean. If you set aside one pencil for this job, it takes on the cone shape you want. We use a 6H or a 4H, and the effect seems to last quite a while.

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Posted by Doughless on Saturday, May 5, 2018 8:05 AM

cefinkjr

I'm thinking that, when released on a grade that's x inches long at y% gradient, a "free rolling" car would roll to the bottom of the grade and z inches more on level track beyond the foot of the grade.

I checked the NMRA web site and found nothing along these lines.  Does anyone have some numbers on this?  I'd like to build a Conformity Test Track for our club and it ought to be able to verify that a car is or is not free rolling.

 

Of course, a club could set its own rules and standards and its own way of calculating compliance. 

It seems like every car will have to be tested anyway in order to pass the free rolling test, so instead of following strict NMRA rules on things (I know, heresy here) have the club set its own standards for what makes sense for its goals.

While you want free rolling equipment, I'd think a situation like Wayne described might cause community discord if someone up the line forgot to "set the brake".

- Douglas

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Posted by doctorwayne on Friday, May 4, 2018 11:50 PM

Chuck, Bob K., and Guy, thank you for your kind words. 

Bob, the boxcar, one of eight fairly heavily-modified cars, is an Athearn Blue Box kit, with trucks from Proto.  I didn't choose the trucks for their free-rolling qualities, but rather for the fact that the National B-1 trucks were introduced in the '30s, the same era in which my layout is set.

BNSF UP and others modeler

Longer trains = need for more free rolling stock.....

 
I'm not overly concerned with having free-rolling cars (nor am I a fan of metal wheels), but to me, longer trains=need for more locomotives. (If the cars roll like bricks, well, that calls for even more locomotives.)
 
Wayne
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Posted by NWP SWP on Friday, May 4, 2018 11:08 PM

Got it.

Steve

If everything seems under control, you're not going fast enough!

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Posted by SeeYou190 on Friday, May 4, 2018 10:48 PM

NWP SWP
How's this?

.

That is probably another bad idea.

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Over-lubrication is a huge problem. Just get a bottle of Labelle 102, 107, and 108. No need to re-invent anything here.

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Each of those bottles contain a lifetime supply. That is how little lubricant you should be using.

.

-Kevin

.

Living the dream.

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Posted by NWP SWP on Friday, May 4, 2018 10:42 PM

How's this?

It used to lubricate o-rings on pool equipment, it's basically the same as the WS stuff but half the price, Vaseline is probably a horrible idea now that I'm thinking about it, it is a gunk magnet and tends to run over time.

Steve

If everything seems under control, you're not going fast enough!

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Posted by SeeYou190 on Friday, May 4, 2018 10:35 PM

NWP SWP
Has anyone thought of taking a toothpick got some Vaseline (petroleum jelly) and put a small dot on the "bearing" bezels on the trucks?

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Vaseline is a very bad idea.

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It is great for automatic transmission assembly, but other than that one application it should be avoided for use as a lubricant.

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Almost anything else is a better option.

.

-Kevin

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Living the dream.

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Posted by "JaBear" on Friday, May 4, 2018 10:25 PM

NWP SWP
Has anyone thought of taking a toothpick got some Vaseline (petroleum jelly) and put a small dot on the "bearing" bezels on the trucks?

Not a good idea, as over time it will act as a “grunge magnet”.
I use this….
 
…sparingly!
 
My 2 CentsThe Bear.

"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."

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Posted by NWP SWP on Friday, May 4, 2018 8:54 PM

Has anyone thought of taking a toothpick got some Vaseline (petroleum jelly) and put a small dot on the "bearing" bezels on the trucks? Why? To reduce friction between the axle and truck.

Steve

If everything seems under control, you're not going fast enough!

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Posted by BNSF UP and others modeler on Friday, May 4, 2018 8:13 PM

Longer trains = need for more free rolling stock. I personally am going to push mine to the tops of free rolling, which will cost more time and money than the reasonable "freerollage" that already exists, but I crave long trains.

I'm beginning to realize that Windows 10 and sound decoders have a lot in common. There are so many things you have to change in order to get them to work the way you want.

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Posted by NWP SWP on Friday, May 4, 2018 8:01 PM

That's another great idea.

Steve

If everything seems under control, you're not going fast enough!

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Posted by xboxtravis7992 on Friday, May 4, 2018 7:57 PM

Well with simple kinematics, an understanding of kinetic energy, angular momentum, and an idea of the coefficient of friction involved between the rails and the wheels we can calculate all we need to know about the movement of a car downhill, even calculating its speed after it collides with any cars further down line... 

Sorry I just wrapped up a physics class, I couldn't resist making the joke. Stick out tongue

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Posted by gregc on Friday, May 4, 2018 6:22 PM

did you see the low-tech solution posted above

MisterBeasley

You can see the tuft of field grass I put between the ties to hold the cars and keep them from rolling.

greg - Philadelphia & Reading / Reading

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Posted by NWP SWP on Friday, May 4, 2018 5:15 PM

To solve the freerolling car rolling down grade from where it's been spotted either have a working coupler on a bump stop and couple the car(s) to it, or using a switch motor or such have a pin come up through the rails OR a wire or something that goes across a rail to act as chuck.

Steve

If everything seems under control, you're not going fast enough!

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Posted by DigitalGriffin on Friday, May 4, 2018 4:18 PM

The official definition:

Anything over a 1% grade will start moving on its own if it is free rolling.

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

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Posted by dknelson on Friday, May 4, 2018 3:35 PM

cefinkjr
put the car in a friend's yard that was thought to be flat. That car quickly found the low spot in the middle of the yard.

So called "bowl" yards are and were prototypical.  The layout owner was a better modeler than he knew!

Dave Nelson

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Posted by cefinkjr on Friday, May 4, 2018 2:53 PM

Dave

Your mention of Lindberg reminded me of a time when their trucks were first available (I think before Lindberg's cars).  I had replaced the original trucks under a freight car with Lindbergs and put the car in a friend's yard that was thought to be flat.  That car quickly found the low spot in the middle of the yard.

Chuck
Allen, TX

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Posted by cefinkjr on Friday, May 4, 2018 2:45 PM

MisterBeasley
 
gregc
but i have a car that rolls in spots on my flat layout. I certainly can't see the grade, nor intended there to be one. The problem is when i spot a car at a spur, it will roll off the end of the spur. so while there may be a requirement that cars roll on a specified grade, I think there is such a thing as a car rolling too freely.

 

That's a problem I have, too.

I had a problem a few weeks ago with a slight grade on an industrial lead.  I needed to leave a tank car on that lead while I pulled others from the track where the tank car was to be spotted.  But when I shoved it in the clear (with delayed uncoupling), it wouldn't stay there; it just followed me back out.  I finally drafted a Corvette that was waiting at a grade crossing to hold the tank car back.  (Sorry 'bout that, Corvette fans.)

I'm told that the grade on that lead has been eliminated (by shoring up that part of the railroad) but I'm prepared for the next runaway: I bought some old-fashioned pink rubber erasers and narrowed them to fit between HO rails.  They're heavy enough to stop most cars, the rubber keeps them from sliding on the ties, and their color makes it harder for me to forget that I put them there.  Biggest problem with them is remembering which pocket of my "operating" vest they're in.  I think I paid less than $2 for a package of three.

Chuck
Allen, TX

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Posted by SeeYou190 on Friday, May 4, 2018 2:34 PM

Cars that are very free rolling are a problem.

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My problem has manifested itself in my caboose fleet. All my cabooses are brass models. I have installed Ticky caboose trucks on all od these. This is because the plastic wheels and sideframes eliminate the possibility of intermittend dhort circuits.

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Unfortunately (for me), these Ticky trucks roll very freely.

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I use Kadee #308 under track magnets, and these are powerful enough to pull the caboose forward as it approaches, cause slack in the coupler, and then have an accidental uncoupling. The only manet part on any of my rolling stock is the uncoupler pin. No steel axles, weights, or hardware is allowed. That #308 uncoupler is powerful enough to draw on the pin and cause the uncoupling.

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I have tried different axles in the Ticky trucks, but not been able to find a combination that provides enough drag. I tried adding brass wipers, but that was a temporary fix bacuase they ate into the plastic axles.

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In N scale Micro-Trains makes a truck restraining spring to combat this issue.

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The only grade on my layout will be into branch line staging, five car train length maximum. On the rest of the layout it will be level running with 14 car maximum train lengths.

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Free rolling is a problem for me. I do not want runaways on spurs or accidental uncouplings.

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-Kevin

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Living the dream.

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Posted by bogp40 on Friday, May 4, 2018 11:34 AM

MisterBeasley

 

 
gregc
but i have a car that rolls in spots on my flat layout. I certainly can't see the grade, nor intended there to be one. The problem is when i spot a car at a spur, it will roll off the end of the spur. so while there may be a requirement that cars roll on a specified grade, I think there is such a thing as a car rolling too freely.

 

That's a problem I have, too.

To my knowledge, I laid this scrapyard spur on a flat and level surface, but it ended up with a minor grade.  It was fine until I replaced the old (like 40 years old) plastic wheels with metal ones.  When I would spot the cars at the end of the spur (bottom of the picture) they would roll all the way out to the main at the top.  You can see the tuft of field grass I put between the ties to hold the cars and keep them from rolling.

I've also got some of the Kadee powerful under-track uncoupling magnets.  With very free-rolling cars, I can't use the "delayed" uncoupling feature because the magnets are so strong that they pull the uncoupled cars right back over the magnet as I pull the engine back.

 

Spotting cars on a grade, many times however slight, can be a problem. We had a few sidings on the old layout that had some grade to them. Years ago before the use of metal wheels and better rolling stock, this may not have been an issue. The problem was solved by placing a series of "bristles" monofiliment line drilled and glued between the rails (some have used thin bronze wire, but they can give you a nasty poke). These were just tall enough to contact the axle but wouldn't impede the placement of rolling over to spot cars. You may need to figure the average car placements and where to place the filiments. Some longer sidings where you may spot at a few different industries, you may need them at multiple places.

Modeling B&O- Chessie  Bob K.  www.ssmrc.org

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Posted by trainnut1250 on Friday, May 4, 2018 11:33 AM

Wayne,

 

Love your explanation. Sense of humor and fun.....CoolCoolCoolCool Thanks for taking the time to put that together.....

Does free rolling really need to be defined beyond a certain point (clubs? maybe yes)?? I will say that "free rolling' trucks (however you define them) help quite a bit when it comes to climbing grades and overall operational reliability and smoothness.

Guy

see stuff at: the Willoughby Line Site

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