reducing mechanical noise transmission

Hi all,

I have not been around here for a bit but eventually managed to get some time in the workshop and things are beginning to happen. I have been working on my plan to minimise the amount of transmitted noise caused by the train running over the trackbed. You may remember my plywood-underlay-plywood experiments. I think this may work but it is very time consuming to construct and fairly pricey due to the amount of materials consumed. I am now trying a much simpler system where the trackbed is supported on risers topped with a block of underlay material. Building is under way and I will post some pictures once I have the track down. If you would like to see the day to day progress in detail have a look at my workshop blog HERE 

Ralph ;-)

 

Good to see you back Ralph.  Hope you've been busy whilst you've been away.

Regarding your "silent running" experiments, "Mascotia" in Perth, Australia is doing just that.  he's an ex submariner and learn about sound insulation whilst stalking enemy battleships ……………….:roll::roll::roll:

See his post No 7 here:

http://yourmodelrailway.net/view_topic.php?id=9686&forum_id=21&highlight=submarine

[user=6]Petermac[/user] wrote:

Regarding your "silent running" experiments, "Mascotia" in Perth, Australia is doing just that.  he's an ex submariner and learn about sound insulation whilst stalking enemy battleships ……………….:roll::roll::roll:

See his post No 7 here:

http://yourmodelrailway.net/view_topic.php?id=9686&forum_id=21&highlight=submarine

Hi Peter and all,

It is good to be back here and although I have not been "busy" for the past couple of years all that is about to change, I'll tell you more when it happens…

Matt is using the same principle I have adopted - 9000 miles away! I an going a bit further by separating the track from the road bed - Ill post some pictures later toady as I an doing it now…

It's good to be back!

Ralph ;-)

A bit further on. A late night tonight, burning the midnight oil. The contours have been fitted and the track bed is in place. It all needs time for the glue to go off properly before the underlay is trimmed and the outside is sanded and undecorated.



…More details can be found on my blog HERE

Ralph

Final update …

One of the things I was messing with last time I was here was sound transmission, or rather the reduction of it. To cut a long story short, I don't think it makes much difference. Below is the section I was working on and once the landscaping hard shell was added it was still reasonably quiet but not noticeably more-so than any other method of track-laying onto foam or cork (or both)



The sandwich of underlay and ply also looked promising but again the difference was not worth the effort or cost involved.



The end result just proved that it seems to be a wast of time trying to improve on the tried and tested. Hay-Ho it was worth a go!

Track-laying at Smokie Ridge will follow conventional methods.

Ralph ;-)

Interesting experiment of yours Ralph.
Also good to see you back.
That sound proofing with track to ply is all very hit and miss.
Funny thing if you use the old trainset method and just pin the track it stays reasonably quite.

As soon as you introduce glue. Either to the track base or to ballast. Then the noise level sharply rises.
It must be a physic's thing?

regards,

Derek

Funny, I was just having a re-read of Rice's Finescale Track book.  In it he references the work of Ken Northwood who advocated a floating track idea back in the 50s.  It consists of a layer of "rubber" glued to the baseboard.  The track is glued to "stiff paper" and lightly pinned to sit on the rubber strip.  This was published in Model Railroader - good luck finding it.  Decoupling is the technical term and I daresay Mascotia is working to the same principles.  I did some experimentation more than 10 years ago (I was bright eyed then) but found it to be impractical and reverted to the cork underlay method. 


 The idea is based on the way track and stock interacted before modernisation.  Locos tended to have pretty rigid suspension and it was the trackbed that flexed as trains passed over it.  Nowadays (and I'm going off Rice here), track is designed to be much more rigid with stock having much more flexible suspension systems.  Heritage stock and steam locos especially are generally viewed with a jaundiced eye by the PW engineers of today.


 John:pathead

I'm using a double layer of sound deadening materials for my layout which, while it doesn't totally eliminate track noise, does certainly reduce it to an acceptable level.

The first layer is 3mm cork which is fixed over the whole board area with Copydex. I then lay 2mm Plastazote just where the tracks will be, again fixed down with Copydex. The purpose of the cork layer is to isolate the ballast from the plywood baseboard when forming the ballast shoulders as, once it is fixed in place with diluted adhesive which goes hard when dry, it would otherwise form an acoustic 'bridge' between the track and the underlaying board top and totally defeat the sound deadening properties of the Plastazote.

Good idea Trevor,
Also John and that old 1950,s method.
The thing is the plywood board.
Now I have often wondered if isolating the board itself from the frame assuming a softwood frame and supporting legs and crossbraces.
Say useing hard rubber strip on top of the frame and crossbraces thus isolating the ply board would make any difference.?.
Still the ply itself probably acts like a drum skin anyway so one maybe at nothing with this idea?

regards,

Derek

Lets face it trains make noise, models make more than necessary when they are driven too fast. Because of the design of my layout, the curves used, and the pointwork, I have a speed limit of scale 50 MPH, the noise is minimal, and not worth worrying about - are we worrying too much, or should we use more realistic speeds, over engineering could stop you having fun ????

I wonder if clear silicon sealer between frame and baseboard would hold and also would it actually deaden the sound?.

Hi Guys!

In the end I decided that even after incorporating a lot of sound deadening the amount of difference it all made was minimal. In the end I opted to use cork and foam but the other way around to Chinahand's method with my cork on top.



I also opted to use a block of sound deadening 'felt' (used as laminate flooring underlay and sold in 'tiles') between the riser and the 12mm MDF track substrate.



I am not sure how much difference this really makes but at least I know I have done what I can without costing the earth.

Ralph ;-)

I did try silicon sealer but it was so difficult to get a thin, even layer before it went 'off' that I gave up. Copydex is a latex rubber adhesive so does, itself, have some sound insulation properties.

Incidentally, it's not necessary to buy the actual 'Copydex' adhesive as there are several identical adhesives on the market which are much cheaper. I bought 5 litres of this one for the same price as for 1 litre of Copydex. http://www.ebay.co.uk/itm/Ball-Styccobond-F1-Latex-Carpet-Adhesive-5-Litre-/261024565344?pt=UK_Crafts_Cardmaking_Scrapbooking_Glue_Tape_EH&hash=item3cc646c860#ht_1718wt_1250

I get very little rail noise, clickety-clacks over points but not much else. Cork tile track bed over 2" polystyrene insulation sheets.

Why bother at all?  Railways, and particularly locomotives, are noisy.  And if you are going to exhibit your layout, you won't even notice any noise in a busy exhibition hall.  As for foam, how long before it breaks down?  I have just lifted the foam carpet underlay in the bedroom and, after fifteen years, a lot of it has reduced to dust.  You might easily have your layout for that period of time.  And on that depressing note …

Terry

[user=1151]bike2steam[/user] wrote:

Lets face it trains make noise, models make more than necessary when they are driven too fast. Because of the design of my layout, the curves used, and the pointwork, I have a speed limit of scale 50 MPH, the noise is minimal, and not worth worrying about - are we worrying too much, or should we use more realistic speeds, over engineering could stop you having fun ????

:) I suppose Paul noise is relative when it comes to running our railways.

There are those who have to share their accomadation.

Some people/relatives can get upset when your 11pm express thunders along in a room above the TV room :shock:.

Add that to a loco with sound installed and one has the making for lets say a little domestic friction!

Not that I am bothered by such minor details. I live alone and the nearest house to me is a quarter of a mile away.

Of course my attitude may have something to do with being without company? :???:

regards,

Derek