The other benchwork thread got me thinking. What is the best way for minimzing that deep droning sound when the train rolls over the track? I’ve read where it is the vibration of the moving train that causes the resonation in the benchwork when everything is glued, nailed, and screwed tightly together. I’ve noticed it mostly after ballasting with white glue and water, which helps to transmit the vibration and noise from the track throughout the benchwork. I’ve read once where putting homosote below the plywood works well.
Has anybody built benchwork and roadbed with quietness being a goal and what have you found to be the best method?
I recall an article in Railroad Model Craftsman sometime in the late '80s or early '90s that suggested that uneven joist spacing under the plywood would cut down on accumulated sound transmission. Or, you could turn your DCC sound waaaaay up…
There is a very good article in the “How to build Realistic Reliable Track” published by Kalmbach this year about all the roabed we use and especialy the one which is the less noisy.
It seems that the Cork/camper tape lay on plywood (subroabed) or homabed/camper tape are far the less noisy combination.
However, on my own Nscale Maclau river, I use only cork lay on the subroabed plywood which is 18mm thick and have no particular noise. On the yard there is no cork and still no big noise; I suppose it’s because of the thickness of the plywood, 18mm or a little more than a 2/3 inch.
As you have found out, the track got real noisy after you ballasted. White or Yellow carpenters glue dries ‘rock hard’ and the noise will be transmitted to the layout. I use ‘Matte Medium’ which dries to a ‘rubber like’ consistancy and does not transmitt the niose. A lot of folks just use diluted white glue because it is less expensive that matte medium - but you will get a lot of ‘noise’ transmitted to the layout. Our club railroad has a foam base, with cork roadbed & track glued to the foam. We notice a lot of ‘drumming’ noise with this combination until we ballasted with real rock ballast(Arizona Rock & Mineral) that was glued down with Matte Medium. Very little additional noise is transmitted to the foam.
My own layout uses a sandwich of (from the bottom up):
Thin plywood - sometimes stiffened with steel angle stock.
Fan-fold underlayment (thin extruded foam)
Cardstock track template.
Flex track (or wooden ties to which rail is spiked)
All held together with latex caulk.
In some locations, the plywood gives way to steel studs laid trough-fashion, like a through girder bridge.
Since all of this is unballasted, it has been rather silent - a lot less noisy than prototype railway equipment seen at the same (scale) distance. I rather suspect that the rubbery caulk is a major factor.
In the not very distant future I will finally burst out of the Netherworld, and will have to start laying track which is meant to be seen in all its ballasted glory. If matte medium gives a flexible-like-caulk result, that’s what I’ll use.
Chuck (Modeling Central Japan in September, 1964 - quietly)
The acoustic engineers will tell you that dual densities situated against each other will serve to dampen sounds quite effectively. In fact, they do that to all acoustic waves, not just the freqs we can hear. Dual density materials placed in shallow metal cups are used at the bases of heavy tripod legs on the mounts of amateur telescopes because they dampen vibrations caused by people walking around the tripod or people touching the instrument, itself.
So, cork will do an okay job in some applications, but it will be greatly enhanced by using something even harder, such as set caulking, between itself and the plastic ties. Or, something softer, maybe a thin ribbon of rubber foam. Note that dried caulk is still somewhat pliable, so it isn’t hard and unyielding as the wood on the other side of the cork.
And I agree, ballasting with glue doesn’t do much good in the way of sound attenuation. More like sound propagation. [xx(]
Does anybody think that putting a bead of latex caulk between framing members, or between the foam/plywood base and the horizontal support rafters limit any vibration being transmitted throughout the benchwork? Maybe when the screws are tightened it would negate any benefit of the latex cushion.
When you mentioned tightening screws, you answered your own question. The direct connection through the screw completely bypasses the caulk and any effect it might have.
In the caulked-together sandwich I described above, there are no fasteners that penetrate all the way from top to bottom, and very few (other than track spikes) that penetrate two layers.
Please, Sir, it ain’t that hard!. Use Homasote and all will be quiet. I’ve been using it for years with virtually NO trouble at all, despite what the informed elite will tell you. Plus, it’s CHEAP!
Highly realistic model track and roadbed would be noisy, very noisy. Real track creaks and groans, bangs pops and squeals. Locomotives are noisy and shake the ground, freight cars bang and clang and thump down the track with flatspotted wheels. Couplers squeak and bang, wheel bearings scream. Why do you want quiet benchwork and roadbed? Surely not to be realistic in any way. Why not just build your layout then play a loop recording of a rail yard very loudly in the room? Quiet railroads? Piffle. Sound my friend, that is what brings a dead piece of plywood to life.
I agree with Jack on this one: what’s the point? Clandestine model railroading so that the neighbours won’t discover that you’re, gasp, playing with trains? [swg] I’m not a big fan of noise, but how long are you willing to sit at the mouth of that tunnel, waiting for your silent train to emerge? By the time the smoke appears at the portal, it’s too late to shut 'er down. [:O] If you really want quiet trains, instead of replacing those plastic wheels that you’ve removed and thrown away, simply don’t! [:P] That’ll cut down on your track cleaning chores, too. [:-^]
My word! Ready-to-run and now you want it quiet, too? [(-D]
Wayne and Jack, the answer is that for those with sound-equipped HO scale engines, the rolling noise (a roar at times, if the circumstances are right…) competes heavily with speakers that have their volume turned to the middle settings so that there is less distortion. If you are going to pay for sound, you’d like to hear it, and not the model rolling sounds which are quite unlike what you hear trackside in the real world.
Well, for me, railroads are appealing to the sense of sight. Not much about them is appealing to the sense of hearing. They ain’t Mozart.
Adding even more realism, how about the sense of smell? I thought about doing a layout based upon 1920’s texas cattle country, but my wife objected to the suggestions I had for simulating the smell of a unit cattle train.
Wayne, I agree. I can’t stand more than two engines sounding anywhere on my layout. The speaker sounds aren’t exactly first class to begin with, but they don’t scale worth a darn. So you get a BLI K4s’ cross compounds banging away like mad, or the injectors wailing, except that it is 600 scale yards away…and trying hard to outdo the J1 I am intent upon. Grrrrr…
But, with the one or two being all the sound supplied to my railroading enjoyment at any one time, a lot of roar and rumble just doesn’t work…for me. It has to be one or t’udder. [:)]
Doug, my trestle is the only ‘olfactory’ item on my layout, and I had to do it the ‘beg for forgiveness’ way rather than the ask She-Who-Must-be-Obeyed way. I used a rather generous supply of real creosote oil that my Dad left me when I inherited the place. I used maybe two teaspoons on the little wood surface of all the timbers…not much at all…and it was GREAT the first three days. Then, it was gone. I have to get my nose right up against the timbers, which doesn’t exactly elicit an indulgent smile from She when she catches me doing it. [:D]
I’ve only heard of Homasote being used in conjunction with track spikes. Do you know, can you attach cork roadbed, or other materials, to Homasote with latex caulk, or even white/yellow glue? It seems like those products might soak into the Homasote.
Never mind 1920’s Texas cattle country. Try driving from Amarillo to Clovis right now. The BNSF delivers unit trains of cattle feed to those Rhode Island-size feedlots (with the mountains of scraped-together bovine droppings…)
As far as sound - I’ve heard doubleheaded D51 class 2-8-2s tackling a 2.5% grade from a standing start. Nobody will ever mistake THAT for freeway noise. Unfortunately, nobody has figured out how to get a speaker the size of a quarter to reproduce that short-cutoff cannonade.
Chuck (Modeling Central Japan in September, 1964 - as quietly as possible)
I understand onboard sound is expensive, I’ve heard it and it’s all very nice if you want to pretend you are in the cab of the loco and only want to hear that. To date I’ve never seen a layout built from the perspective of the cab. Track makes as much if not more noise than any loco.
I’ve got MP3 recordings of differing rail action that I can play through normal household speakers at volume and I can assure the doubters that actual rail sounds makes a difference in realism that the eye fails to satisfy. Try it just once and see for yourself. Quiet benchwork? Whatever for?