How quiet is benchwork made with 1/8 " masonite and 2" XPS foam insulation board on top of L-girder benchwork?
Can I lay flextrack directly on XPS insulation board , or should I put a layer of cork between the track and the insulation board?
to the forum, your inital posts are delayed for moderation.
This has been discussed in the past. People are concerned about the drum head effect but that may, according to posts, be affected by what you use to glue your ballast.
I like the look of cork roadbed, so that is what I am using.
Henry
COB Potomac & Northern
Shenandoah Valley
The shorter the unsupported gaps between stringers or joists below the foamboard, even with masonite on top, the less noisy it will be....generally. Long unsupported spans will be noisier because the sound waves find their niche there.
What you want, if possible, is multiple densities of materials, so cork over the foamboard is a good solid step in the right direction. But, if we pour ballast, groom it, and then make it solid and monolithic with glues, you will find a lot more noise transmitted to the foam surface. So, you really want to separate the glued ballast from the main surface of the layout. An intervening layer of drawer liner material or something, cut into suitable widths and lengths, will help a lot. You'll have to figure out how to keep the ballast and tracks in one place and aligned in geometry as you like it, but that's what monolithic (hardened) ballast helps to do.
Multiple layers, dual or triple densities, and try to isolate the tracks and ballast so that vibrations don't pass down and make your extruded insulation foam vibrate. Three or four spaced 1X3/4 joists should help as well.
I put Micro Engineering cork between the 2" sub-roadbed and track.
Not being a sound engineer, I have no scientific reasoning but doesn't the type of locos you run also matter for sound?
Sound is transmitted by rigid, vibrating materials. Sound is absorbed by hanging cloth, or rugs on the floor.
Latex chalk, thinly spread holds cork quite well to foam, and then the same material hold track nicely. The caulk never become totally rigid.
I don't have much noise from running trains on my layout as much of the mainline track is on cork roadbed.Staging tracks are on bare plywood, but with solid supports, noise is minimal.
Of course, my definition of noise might not be the same as other model railroaders, as after almost 40 years in a steel mill, noise was part of the job, and often loud enough to drown-out even real locomotives when they entered the mill.
Wayne
I need to get more trains running before I can comment meaningfully about noise! But I have been warned that my benchwork style -- the David Barrow domino design -- might amplify noise. One person said it looked like a big guitar. I do use homasote under cork roadbed, with flexible adhesive calk securing the roadbed and the track all of which should inhibit noise but 1) the homasote has been sealed with shellac to discourage warping due to seasonal changes and 2) the track is ballasted. That adds rigidity and thus as mentioned above noise transmission to the situation.
Ironically compared to when I started in the hobby, back then everyone was in love with the new nylon and Delrin and other plastic trucks and wheels which were praised for being so silent and smooth. Now everyone wants metal again.
Wayne as so often might have the best solution. Work in a steel mill long enough and you don't hear the noise!
Dave "eh, what's that sonny?" Nelson
bellj9 How quiet is benchwork made with 1/8 " masonite and 2" XPS foam insulation board on top of L-girder benchwork? Can I lay flextrack directly on XPS insulation board , or should I put a layer of cork between the track and the insulation board?
May I ask what the concern is with noise? I've never found noise from my HO scale trains to be objectionable. The trains are the loudest when travelling on the main, but that's relative since I can't hear the wheels at all, beyond clicking over turnout frogs, during lower speed operations like switching. The motor and drivetrain in the non-sound-equipped locomotives are the only noticeable sounds.
As others noted, noise is subjective to the listener. I ran a train around the layout a few minutes ago while nobody else was home, and agree that ballast does cause a different sound, not so much louder as higher pitched, as if it were reflecting the sound waves rather than absorbing them. No matter where the train was though, the sound direction always seemed to come from the top of the layout rather than underneath (cork roadbed on 2" foam on 1/2" plywood on 1"x4" open grid benchwork).
AEP528May I ask what the concern is with noise? I've never found noise from my HO scale trains to be objectionable.
Same here... My trains don't make much noise. The loudest sound is the metal Kadee wheels gliding over the metal rails and clickety-clacking on the joints.
What noise is all this concern over?
Only my old Tenshodo 0-8-0 makes a lot of motor and gear noise, benchwork will not help with any of that. Again, I do not find it objectionable.
-Kevin
Living the dream.
I've never understood the noise issue either. Our layouts are a miniture version of the one of the biggest and noisiest forms of transportation there is!
Go stand trackside, and enjoy it! As a railfan, I sure do.
I have a solid wood base covered with 2" foam, trackbed is right on the foam. I have no issues, but, for me, noise was never an issue.
Have fun.
Mike.
My You Tube
There have been some experiments on the topic of noise.
I think the conclusion was essentially that the heavier or denser the roadbed/subroadbed/benchork is, the less noise it produces. The noise is caused by the trains vibrating the subroadbed, so, if it was made of a very heavy material that the trains could not vibrate, concrete for example, there would be no noise at all.
So materials like cork over 3/4 plywood supported by 2x4s all tied together tightly should tend to produce less noise than less dense roadbed over foam subroadbed supported by a lightweight grid. The latter producing more "drumming" because its vibrating more, in theory.
Then there is the issue of transferring the vibration to the subroadbed "drum". Most people experience that when they glue down there ballast, the hard crust transfers more of the vibrations to the drum and the layout gets noisier.
So, loose track on loose roadbed is probably noise free compared to securing it all to the subroadbed. Not that you'd want to do that.
But I think the experiments concluded that the noise difference between the different choices we typically build our layouts isn't enough to outway most of the other reasons/advantages to building the way we choose. In OPs case portability and need for light weight.
- Douglas
Glued ballast vs loose or no ballast isn't about transmitting sound, it's about reflecting sound. It's the same effect as taking the rug out of a room. Noises in the room don't sound louder because the sound waves are now transmitting through the floor. They sound "louder" because more of the higher frequencies are now reflecting back to the observer's ears. If you don't believe that, then consider this: You don't get an echo unless the sound waves are bouncing back.
I put louder in quotes because the source volume hasn't changed; the ear is simply receiving more frequencies.
Regardless, model trains are so lightweight compared to nearly any form of benchwork or support that they'll never produce loud, objectionable sounds.
AEP528 Glued ballast vs loose or no ballast isn't about transmitting sound, it's about reflecting sound. It's the same effect as taking the rug out of a room. Noises in the room don't sound louder because the sound waves are now transmitting through the floor. They sound "louder" because more of the higher frequencies are now reflecting back to the observer's ears. If you don't believe that, then consider this: You don't get an echo unless the sound waves are bouncing back. I put louder in quotes because the source volume hasn't changed; the ear is simply receiving more frequencies. Regardless, model trains are so lightweight compared to nearly any form of benchwork or support that they'll never produce loud, objectionable sounds.
Simon
Doughless There have been some experiments on the topic of noise. I think the conclusion was essentially that the heavier or denser the roadbed/subroadbed/benchork is, the less noise it produces. The noise is caused by the trains vibrating the subroadbed, so, if it was made of a very heavy material that the trains could not vibrate, concrete for example, there would be no noise at all. So materials like cork over 3/4 plywood supported by 2x4s all tied together tightly should tend to produce less noise than less dense roadbed over foam subroadbed supported by a lightweight grid. The latter producing more "drumming" because its vibrating more, in theory. Then there is the issue of transferring the vibration to the subroadbed "drum". Most people experience that when they glue down there ballast, the hard crust transfers more of the vibrations to the drum and the layout gets noisier. So, loose track on loose roadbed is probably noise free compared to securing it all to the subroadbed. Not that you'd want to do that. But I think the experiments concluded that the noise difference between the different choices we typically build our layouts isn't enough to outway most of the other reasons/advantages to building the way we choose. In OPs case portability and need for light weight.
And this is exactly why I build heavy benchwork, don't use foam, use homasote roadbed rather than cork.
You can't prevent surface reflection of noise, but you can prevent turning the benchwork or roadbed into a drum.
One of my other hobbies is HiFi, I have been designing and building speaker systems for 45 years. Heavy and dense is best.
Sheldon