One good reason, unrelated to noise, to have more under your cork roadbed than just the tabletop, is that the more elevation you have, the easier it is to model culverts, drainage ditches, and other topographical features of prototype railroad right of way. 1/2" plywood and 1/2" homasote plus cork would be useful for that, quite apart from any other benefits.
Another reason would be if you like to use Peco's attached-to-the-bottom-of-the-ties switch machine and don't feel like routing out the plywood underlay. The higher the turnout the more room there is for the Peco machine (which also comes with an extending rod version for greater distance, although there are limits to that distance).
Dave Nelson
PS relative to Dr Wayne's comment about metal wheels and noise the other day I was trying out the various freight cars which I had just retro-fitted with after-market cushion underframe extended coupler pockets (my safer-at-home coronavirus project). I have an S curve crossover on my layout which tends to be something of a torture chamber for rolling stock so I was rolling the cars back and forth, coupled and uncoupled. All have metal wheels but there was no locomotive noise to mask the hiss of the metal wheels on the track. My wife finely came into the train room and asked "WHAT the heck is that strange sound?" She said it sounded like I was using a fire extinguisher!
PPS I also discovered why that S curve crossover was such a torture chamber. One Peco large radius turnout was very tight in gauge. So tight the NMRA template gauge got stuck! And here I had been swapping out wheel sets and increasing weight in the cars all this time. Now I need to make a new torture test for newly completed rolling stock I guess. I think I fixed the turnout.
BigDaddy Thickness is not an issue with switch rods. Some swap out the tortoise wire for something larger in diameter.
Thickness is not an issue with switch rods. Some swap out the tortoise wire for something larger in diameter.
Although, if you're using the Atlas under the table machines, the plywood-Homasote-cork sandwich exceeds the length of the Atlas rod.
With the exception of my modules, every layout I've ever built has been 1/2 ply and 1/2 Homasote with cork roadbed. Dad handed down this way as the Holy Writ and it included the part about sound. However, in retrospect, I honestly can't tell the difference between the straight plywood on my modules and the sandwich on my previous layouts. Part of it might be that the locomotive drives are way quieter than they used to be.
I've been planning my largest and most ambitious layout ever and the siren call of the Homasote sandwich is strong. I really, really, really like how easy it is to attach cork and track without adhesives because it is so reconfigurable. But...Homasote runs $31 a sheet. Half inch ply is $24, putting my per square foot cost at $1.72. Or I can get 3/4 (23/32) ply for $30 a sheet. That's $0.94 a square foot.
Is it worth almost doubling the cost of your subroadbed for a modicum of sound reduction that may or may not exist? Even the ease of spiking is a transient feature...
peahrens He does not discuss much about the final element; i.e., ballasting. He makes the comment "I found that compared to the choice of roadbed material, ballast had little effect on rolling stock noise". I was a bit surprised at the ballast comment. I just ballasted my cork on 5/8" plywood, about 7 years after laying my flextrack on cork. So I was quite used to the sounds with unballasted track. I secured my ballast with white glue, and it made a significant difference, with noises amplified. I had read about this, but did not try the matte medium as glue that some say would moderate the effect. I do have DCC sound locos, but I do notice the increased rolling stock noise and would prefer they not be so noticeable. Perhaps part of it is simply getting used to the change. Overall, I so far find that noise somewhat significant and unrealistic. Of course, I have no comparison with a "better" roadbed choice. But I made a conscious decision to go with the standard cork and white glue for ballast.
He does not discuss much about the final element; i.e., ballasting. He makes the comment "I found that compared to the choice of roadbed material, ballast had little effect on rolling stock noise".
I was a bit surprised at the ballast comment. I just ballasted my cork on 5/8" plywood, about 7 years after laying my flextrack on cork. So I was quite used to the sounds with unballasted track. I secured my ballast with white glue, and it made a significant difference, with noises amplified. I had read about this, but did not try the matte medium as glue that some say would moderate the effect. I do have DCC sound locos, but I do notice the increased rolling stock noise and would prefer they not be so noticeable. Perhaps part of it is simply getting used to the change. Overall, I so far find that noise somewhat significant and unrealistic. Of course, I have no comparison with a "better" roadbed choice. But I made a conscious decision to go with the standard cork and white glue for ballast.
Alton Junction
If you can find a copy of MR Special Issue "How to Build Realistic Reliable Track", there is a related article "Quiet Roadbed, Better Train Sounds" by Bob Kingsnorth. Unfortunately, the Special Issue does not seem to be available in the Kalmbach store nor on Amazon or EBay. I will not attempt to explain or defend all the info in the article, but it is interesting.
In the article, Bob reports on 18 combinations of roadbed & flextrack on plywood subroadbed. He "subjectively" evaluated each version by judging high-pitch noise (wheels to rail) and low pitch noise (locomotive related), which he explains. The roadbed types include: cork, camper tape (two types), homabed, flexxbed, 3/8" foam rubber, micore, Ace super firm sponge tape, Track-bed. Nine of the trials included a combination of two of these items as layered roadbed.
Bob tried various adhesives but it seems he mostly used Alex Plus latex caulk. He comments that track nails into the plywood can significantly enhance noise transmission.
The top two roadbed approaches as per his grading were (a) cork on camper tape and (b) homabed on camper tape. The top 5 rated methods were 2 layer roadbed. The first single layer roadbed, camper tape, came in #6. The traditional cork alone was #16 of his list of 18 approaches.
I was a bit surprised at the ballast comment. I just ballasted my cork on 5/8" plywood, about 7 years after laying my flextrack on cork. So I was quite used to the sounds with unballasted track. I secured my ballast with white glue, and it made a significant difference, with noises amplified. I had read about this, but did not try the matte medium as glue that some say would moderate the effect. I do have DCC sound locos, but I notice the increased rolling stock noise and would prefer that not be so noticeable. Perhaps part of it is simply getting used to the change. Overall, I so far find the noise somewhat significant and unrealistic. Of course, I have no comparison with a "better" roadbed choice. But I made a conscious decision to go with the standard cork and white glue for ballast.
Paul
Modeling HO with a transition era UP bent
Tim 3 posts in 3 years, you must still be in moderation. Track Fidlers' nickname "Post Hog" is safe for now.
There is a lot of hocus pocus in regards to sound dampening. Some people think that the glue used for ballast makes a difference, some say different layers, plywood, homasote, cork make a differenence. Few people ever say that built the same layout 5 different ways in the same room and here is what they found.
Homasote does make it easy to nail or pin the track down and if you are using caulk (another sound variable) those can be easily removed when the caulk dries.
Homasote is heavy, it can be messy to cut and my local Home Depot won't cut it in the store.
Henry
COB Potomac & Northern
Shenandoah Valley
taholmes160 ...I notice in that series, David Popp chose to put cork directly on the plywood and then track on the cork, Does this provide sufficient sound dampening, or should I try to put a layer of Homosate over it (worried about switch rod lengths etc at that point)
I'm not sure about the switch rod lengths to which you refer, but most switch machines can accommodate fairly thick layout bases, some up to 10" or more.
While a layer of Homasote may decrease noise levels of the moving trains, I'm guessing that once you ballast the track, that noise dampening will be more-or-less negated. My layout is mostly on cork roadbed atop 3/4" plywood, and the only really objectionable noise to me is that created by metal wheels. I don't particularly care for metal wheels or the noise they make (it doesn't sound anything like a real train, despite what many modellers say), but if rolling stock comes with such wheels, I can't be bothered changing them to plastic replacements.
I spent almost four decades in a steel mill - most who haven't have no concept of noise of that kind.
Wayne
Just what sounds are you trying to "dampen" ? The sound of a passing train?
Mike.
My You Tube
Hi Folks: IM planning a layout in N scale -- ive been watching the Canadian Canyons video series, and I notice in that series, David Popp chose to put cork directly on the plywood and then track on the cork, Does this provide sufficient sound dampening, or should I try to put a layer of Homosate over it (worried about switch rod lengths etc at that point)
Your feedback appreciated!
TIM