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Joining the Anti-Slinky Fray
- ZRailFan
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www.zcentralstation.com/index.php/my-z/test-my-blog/entry/avoiding-the-slinky-effect
I'm building a layout, on which I'll test my theses, but if anyone has comments/criticisms, I'd love to hear them. Hoping it's helpful...
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- Socalz44
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An interesting thing I found out was that all MTL couplers were not created equally! Some times a really tiny second tape had to be attached to the other side of the jaw, the side of the jaw facing the next car's coupler.
Final thought. Keep on trying to figure out a solution this is looong overdue, probably because of tooling costs.
Also, I never used my MTL couplers in magnetic uncoupling mode. No time or patience. Keep up the good work. Jim
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- southernnscale
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- t.edmunds
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- ZRailFan
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! I just did a set of eight cars they are 3D printing and designed them so I could add weight to each car
3D printed...cool. That is something I'll have to try someday. Where did you get your design, or did you draw it up yourself?
I'd check the weights. It wouldn't take too much weight to be too heavy, and my table is just an estimate using scale as a guide. I should be getting some track today in the mail, so I can try some things out as well (no local shop carries Z, so everything is mail order). But I'd love to know what they weight so we can zero in on an ideal weight. It may be there isn't a perfect solution, although I also wonder about playing with the springs (harder to do than adding and verifying weight).
Hopefully you'll find the cars are a touch heavy, but if not we are limited by the tiny motors. The body scales well, but not the horsepower. But then I also see many consists being pulled by multiple engines, so that's not so un-prototypical. Are you running DCC and can tailor the power?
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- ZRailFan
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You are hardly the first engineer to attempt to solve this issue in the past decades.
I'm sure not. Just hoping to understand what other folks are seeing and have tried. My thought was to apply the logic used by the existing NMRA standards, but it's just an estimate at the moment. It may be this isn't the solution, or is a partial solution. It's at least something I've not yet come across in my readings.
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- ZRailFan
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I like the metal wheels but I find the lower resistance adds to the slinky effect.
Ah! Could be so. Once I get some track laid I'll experiment.
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- markm
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To increase drag, I've thought about flattening the needle point of the wheel sets, and as much as I like metal wheels, staying with plastic. The other thing to try is adding modified piece of rolling stock to the end of the train. The MTL dummy F7s seem to fix the problem for me. I'm thinking the wheel wipers I'm adding to a boxcar for a FRED will do the same.
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- ZRailFan
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Changing to metal wheels makes the problem worst because the metal wheels result in lower friction in the wheel sockets and between wheels and track.
Interesting. I would have thought crud on the tracks would catch and slow the wheel, causing it to rotate a bit more slowly and lag. Then as the locomotive force pulled the wheel horizontally, it would pop back into line. Kind of like stepping on a wad of chewed gum.
But what you're saying is the metal wheels make it glide as if on ice, so the spring tension is exacerbated. I can see that happening, if the spring tension is great enough, as it appears that it is. In that case what you've suggested is to increase the rolling resistance to exceed the spring tension force. Makes sense.
I wonder if I can't also reduce...well...dampen the spring motion. After all, that's the cause of the issue. Left alone, the spring extends and retracts while the car is moving, still probably due to effects further down the line or due to it's own wheel set dynamics. I have an idea I'll test out when I get some track laid and power applied to the rails.
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- ZRailFan
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These are My own design requested by a friend.
Wow! That is soooo cool. If we ever meet, beer's on me. I have a thousand questions. Having recently rejoined the hobby, I'm still thinking like it was 30 years ago. It never occurred to me to buy a 3D printer. I saw your pics, and I'm completely stunned. I'm a huge tank car fan (no idea why), and wanted to model some sort of drilling/refining scene. With a 3D printer maybe I can. Loved your oil storage tank. Don't wanna go off topic here to that degree, but I might send a PM and ask your opinion on a printer I found on Amazon. Looks most excellent.
Question I have one MTL 50ft flat car running with this group of cars It has a six wheeled truck with MTL wheels but when it runs it sounds just like the real wheels on a train it squeals and seems to drag. I have it running as the last car in the consist. I have checked the wheels and they turn good I even put a little oil and it didn't make a difference at all. What else can I try?
Ooh, good one. I'm no expert, that's for sure, and without actually seeing it, it could be hard to pinpoint exactly.
But sound means vibration, and vibration can come from many sources, so as a mental experiment I try to think of all of the sources. Rubbing, dragging, scraping...stuff like that. When rolling, for the moment assuming no issues between the track and wheel, it can only be coming from the bearing box (well, simulated bearing box, where the wheel set meets the side of the truck) or perhaps a wheel is touching the underside of the car. Even if it seems to roll, is there a tab or burr nearby? Are the points of the axles well-formed? Centered?
Note if a wheel is touching the underside of the car, you'll have to look closely for that with the car in-situ...you'd probably never notice it by lifting the car off the tracks. Does the car lean at all when running, either on straight or curved track?
I'm not sure what oil you used, but if liquid I'd, myself, clean that off and go with dry graphite. At least that's what I've found works better for plastic to plastic friction reduction. There are lithium greases that work well too.
If none of that, is the issue seen mostly on curves? (Returning to track/wheel interface...) A six wheel truck is like a passenger truck, and "back in the day" those used to be temperamental on curves that were tight or too tight. I don't know what the recommended minimum radius is for Z, but in HO you'd not like to see anything less than a good 32", and even that is on the tight side. Doing the math, that works out to be close to 12.5" in Z.
Are the wheels in spec? We don't have nice NMRA gauges like in the larger scales, but if the flanges are even a fraction of a hair too far apart, they'll scrape the rail. The sizes we're talking about are so small I'm not sure an eye could tell, but a nice Vernier caliper could tell us. Compare the flange to flange distance with the six wheel truck with another set of wheels you trust... This is a nice caliper, and on sale too.
www.harborfreight.com/6-inch-digital-caliper-47257.html
Just some thoughts...hopefully helpful.
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- t.edmunds
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Thanks
Tom
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- markm
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t.edmunds wrote: I'm interested in how you are doing the FRED. I have a DDC decoder that I let SOME OF THE SMOKE out of. I thought I could mount it in a box car and use the lighting functions to drive the FRED. Where do you get the wheel wipers or does someone make a truck with pickups?
Thanks
Tom
You're possibly over-thinking the project. Evan Designs makes a battery-powered unit: www.modeltrainsoftware.com/fred.html that I looked at in Portland last year, which IMHO is too big for Z scale. But they also make a slow flasher circuit with a Pico LED that I bought. The circuit is designed for 7-22V and works with DCC and the Rokuhan lighting function. The FRED I'm modeling looks like a WWII walkie-talkie that sits in the coupler and the Pico LED is just the right size.
I'm using axle wipers from Richmond Controls in TX. He's a small operation but I see that Monster Z is selling them. For wheel wipers try: www.sbs4dcc.com/zscalewheelaxlewipers.html
He also produces MTL trucks with the wipers installed.
Mark
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- southernnscale
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www.harborfreight.com/6-inch-digital-caliper-47257.html
Went and picked up the 6" Digital Calipers great price for a metal Caliper! Does measurements in inches and mm. also has the depth gauge also! extra battery came with it, and case. Thanks for letting me know! No scales today have to check out where it is! it should have gotten it by now! Here is another 3D printed Car I need to add to the slinky Fray.
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- ZRailFan
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This is a nice caliper, and on sale too.
www.harborfreight.com/6-inch-digital-caliper-47257.html
Yep...I think that's the same one I mentioned. I use it when doing some work on my cars (restoration), but I've since brought it in from the shop to use for laying some track. Starting a layout and wanna hand-lay all of the track. I have the NZT clearance gauge set, but for turnout work I need other tools.
I'm loving the 3D work you're doing, would love to learn more.
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I was pleased with the scale too...I like the nice little protective cover. Great idea to keep such a small, sensitive measurement tool safe.
Those are some fine-looking cars. Nicely done.
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