Ballasting/noise reduction

[Deltech]

New layout planned.

 

Never ballasted before.

 

Been reading a lot about ballasting nullifying the sound reduction benefits of using cork underlay, and wondered if it would be possible to use the “rubber crumb” they use on artificial football pitches for combined ballast/noise reduction?
 

[spikey]

Having tried several of the recommended methods of reducing the noise, I have established beyond doubt that the only thing that works is to get used to the noise, and worry about something else,

[Miss Prism]

If you're considering a rubber crumb type underlay, make sure it will be unaffected by any paints/liquids/solvents/glues you plan to use for the trackwork.

 

[Pete the Elaner]

If you mean the granules, then possibly, but it sounds like hard work.

Cork does help to deaden the sound & dos it very well. It does this by providing a cushioned surface which still allows the rigidity of the board below to provide the stability the track needs. Just laying rubber crumb would not achieve this.

 

Then things go a little wrong.

Unlike the real railway where the track is fixed down by its own weight & the rigidity of its rails, model track needs to be fixed to the board. Fixing with pins is 1 method. Gluing is another. Both bring back some of the noise which the cork helped to reduce. (I have found pins better than glue in this respect - that has given me an idea..I should take some sound level readings with my phone to back this up).

Most then use another product for ballast & this needs to be fixed down somehow because, like the track itself, it is not heavy enough for gravity to hold it in place. Many use PVA which, as a resin, sets rock hard & bring back all the noise you worked hard to reduce.

I have used Copydex for gluing my track & for ballasting. This sets slightly rubbery, which makes it quieter than PVA, but the difference is not as great as I had hoped.

I can hear the noise drop when trains run on the ballasted scenic section to the glued sections slightly either side.

I then hear the noise level drop again (a bigger drop this time) when they move from the glued track section to the pinned track fiddle yard.

 

1 piece of advice is always worth following:

If you are trying something new to you, try it on a small test piece first.

 

 

[Harlequin]

@ISW of this parish has used a particular floor underlay product. I'll leave him to tell you about that because I haven't tried it.

 

I have used cork and PVA, which is quite noisy when things are running at speed and I have noticed that the sound is much louder when running over a large board that completely covers the baseboard frame than when running on the boards that are just wide enough for the tracks leaving the frame open around them. When you think about it, that's not surprising - the traditional baseboard is not unlike a guitar's sound box or a flat drum.

 

So my suggestion is, no matter what kind of underlay you use, make your baseboards so that they don't amplify the running sounds.

 

[bike2steam]

1 hour ago, Pete the Elaner said:

I have used Copydex for gluing my track & for ballasting. This sets slightly rubbery, which makes it quieter than PVA, but the difference is not as great as I had hoped.

 

Yep, I'd go along with that, but remember full size trains make noise, the faster ya go over scale speed the worse it gets!!!

[ISW]

1 hour ago, Harlequin said:

@ISW of this parish has used a particular floor underlay product. I'll leave him to tell you about that because I haven't tried it.

The underlay I used is called 'Vitrex' and comes in a ~1m wide roll for a total of ~10m2. I picked mine up from Homebase (in UK) for ~£35 a roll. It's 3mm thick and, to my eyes anyway, looks exactly the same as the more expensive Woodlands Scenics stuff. Photo below.

 

I've glued mine to the baseboards (plywood, painted in grey undercoat) with neat PVA. Weights were added while the glue set. Even though the glue around the edges sets reasonably quickly (~12-hours) it can still be 'liquid' in the centre of large pieces of underlay for many days. It can be removed, if required, using a knife to separate an edge, beyond which you can pull it all up easily. You can also 'trim' the shape, for example after tracklaying, by vertical cutting along the required shape / profile and lifting the excess underlay.

 

It does 'seem' to be quieter than cork, but you are never going to make it silent. To keep the noise down make sure you used a thick baseboard with plenty of bracing at no more than ~300mm spacing.

 

Ian

[melmerby]

1 hour ago, Harlequin said:

 

So my suggestion is, no matter what kind of underlay you use, make your baseboards so that they don't amplify the running sounds.

 

You could always fit sound deadening panels to the underside of the baseboard.

I lined the cabinets of some hi-fi speakers I made years ago (before filling them with the recommended foam.)

[Deltech]

4 hours ago, ISW said:

To keep the noise down make sure you used a thick baseboard with plenty of bracing at no more than ~300mm spacing.

Ian

How thick is “a thick baseboard”?

[teaky]

I found similar self-adhesive underlay a little cheaper (£29.50 delivered) on eBay.

 

https://www.ebay.co.uk/itm/Acoustic-Underlay-for-Solid-Wood-Floors-Self-Adhesive-Identical-to-Diall/181158311892

 

I have bought from this seller a couple of times and was happy with the service.

 

[ISW]

20 minutes ago, Deltech said:

How thick is “a thick baseboard”?

And how long is a piece of string ...

 

My basebards are 12mm (lower level) and 9mm (upper level). I'd have gone with 12mm for both, but I needed to keep the weight of the Upper Level down to ease removal. If you really want to keep the vibrations down you'd probably need 18mm, although for practical reasons 12mm seems okay to me.

 

Ian

[Ray Von]

On 14/04/2021 at 08:19, Pete the Elaner said:

I have used Copydex for gluing my track & for ballasting.

Copydex gets my vote, after years of using PVA I am converted! In my experience definitely quieter. 

[Deltech]

On 14/04/2021 at 14:45, teaky said:

I found similar self-adhesive underlay a little cheaper (£29.50 delivered) on eBay.

 

 

teaky,

          did ye use this on top or below the baseboard?

[teaky]

35 minutes ago, Deltech said:

teaky,

          did ye use this on top or below the baseboard?

On top.  It is an alternative to the traditional cork sheet.  It might be cheaper to use plain 3mm foam but because this is self-adhesive it does not need the baseboards to be painted with PVA before laying.  I have to admit that I do not yet have a working layout so I cannot directly testify to the sound deadening.  However, Norman Solomon, who makes a living from laying track amongst other things uses 3mm foam stuck down with PVA and I have visited a sizeable layout which uses his trackwork and the main noise is that of wheels on rail rather than any drumming or reverberation which I find quite acceptable or even pleasant.

 

If budget is less of a concern then Woodland Scenics (ISW mentioned this too) do strips of foam which are the correct width for each track and chamfered at the edges.

 

Going the other way, you could even use the 2mm foam underlay sold for laminate flooring.  This is not self-adhesive but is readily available and inexpensive.  I have used it as intended, under laminate flooring and it does a good job of preventing noise transmission.

[RobinofLoxley]

Some of the noise generated by the railway is reflected from the sides and roof of the building, rather than from the boards.

 

Personally I thought cork useless, but I am in the minority.

 

My first layout I built with a layer of 6mm thick closed cell neoprene foam, with double sided tape on side. It was so effective as a noise reducer that genuinely all you could hear was the loco motor noise plus anything the rest of the rolling stock made. I actually decided it was too quiet. I am using a 2mm thick polythene foam product made by Globe Packaging this time, and I stick it to the baseboard using glue dots, as clearly PVA won't dry for years in such an application. The track is stuck to it using more glue dots, friction from the droppers passing through the baseboard, and where absolutely necessary,  track pins.

[JDW]

Just a random thought - if the layout is permanent, could the ballast be glued down without actually gluing it to the baseboard, and if so, would that help? I'm thinking something like laying a layer of cling film under the track, ballasting on top using PVA or whatever adhesive you prefer, so that the ballast and track are solidly glued together, but not actually stuck to the baseboard. 

[ISW]

11 hours ago, RobinofLoxley said:

I am using a 2mm thick polythene foam product made by Globe Packaging this time, and I stick it to the baseboard using glue dots, as clearly PVA won't dry for years in such an application.

It's certainly slow at fully drying, but mine appears to have taken probably months to dry and not years. Either way, it's a long time. Thankfully, large expanses of underlay are stable enough for gluing track to it after a week or so.

 

Ian