Track Ballasting - Which method?

[Noel]

Hi Folks. Sorry of this has been covered here before. I've searched the forum but did not find a specific thread on the matter.

 

What track ballasting method do folk prefer?

 

Our current layout was 'temporarily' ballasted with foam underlay 20 years ago and it was always the plan to either re-ballast it later once the track plan was finalised, or alternatively lay ballast right up to the existing edges of the form underlay. Many moons ago on previous layouts I had ballasted using paint and various grades of sand, but the noise was deafening. I've read a lot of posts on other forums and watched a lot of youtube clips espousing the various methods, but just wondering what you guys have found works well. The one thing I want to avoid is transferring loud noise to the baseboard, so I like the idea of some form of sound insulation (e.g. cork, form, etc). At the moment there is virtually no noise transmitted into our baseboard due the foam underlay so the layout is nice and quiet (i.e. better to hear sound chips).

[Broithe]

This thread - http://irishrailwaymodeller.com/showthread.php/3735-Using-Roof-Flet-as-a-Ballast-Underlay-Good-or-Bad-idea - did talk a bit about the noise aspect.

[Dave]

Noise is a problem after ballasting, even if you use cork or PU foam which I prefer, but as soon as the ballast touches the baseboard the noise is transferred through the ballast rendering the underlay useless. The method I use to overcome this problem is to glue down a layer of 3mm PU foam wider than the ballast with a bevel edge. I lay the track then ballast the bring the scenery up on the foam to the edge of the ballast. You could add an extra layer of foam under the track to create a shoulder. This works quite well and reduces the noise.

[WRENNEIRE]

I turn off me hearing aid......

[Kirley]

I recall a Model Group in England doing experiments on different type of ballast to get quiet running and their recommendation to to use Bostic instead of PVA as the rubber texture prevented the soundboard effect.

[Noel]

I recall a Model Group in England doing experiments on different type of ballast to get quiet running and their recommendation to to use Bostic instead of PVA as the rubber texture prevented the soundboard effect.

 

Interesting. Bostic to glue the foam to the board I presume, as I can't imagine bostic can be thinned or watered down to use to glue ballast between the sleepers (i.e. use PVA for the ballast and bostic to stick foam to board).

[josefstadt]

In Everard Junction's video 'Building a Model Railway - Part 2 - Planning' (

)he covers the entire baseboard in cork and then uses additional thin cork sheets to raise the track above this level. So the balast never touches the wood of the baseboard.

[Tarabuses]

I am surprised to see that your foam underlay has lasted 20 years. Mine started to disintegrate after about 15 years.

[Noel]

I am surprised to see that your foam underlay has lasted 20 years. Mine started to disintegrate after about 15 years.

I think most of the foam I have is UV resistant. Some of the older hornby style did disintegrate years ago. Mine has been down for 22 years. I plan to replace it anyway.

[BosKonay]

I use woodland scenic foam and use copydex to fix the ballast. It's not silent but it's pretty good.

[Noel]

Thanks Guys for your helpful feedback. Think I will do a few trial sections of all of the above.

[Dhu Varren]

My chosen method, which I have used for more than thirty years, is to build the baseboard with a plywood, chipboard or MDF top, my preference being 3/8” plywood. On top of the plywood is ½” wood fibre insulation board, softboard as it is sometimes known, pinned down and covering at least where the track will be. On top of that, cheap 1/8” cork tiles from the local DIY shop are glued down, and trimmed once the track is laid. The track is then pinned down using Peco track pins, which go into the cork and softboard quite easily, but are retained securely by the cork. Once the track is correctly aligned, ballast is applied dry in the traditional way, and dilute PVA dripped on using an eye dropper, ensuring that the PVA only settles on areas covered by the cork. The combination of cork and insulation board ensures that noise is kept to an acceptable minimum, although there will always be a certain amount of noise even where there is no ballast.

[dave182]

Just thinking out loud, as I am currently building some base boards, would some forms of insulation or foam/polystyrene board underneath the baseboard take any of the sound away? I'm assuming the empty space between the framework and baseboard is contributing to the noise? Or am I away off the mark?

[BosKonay]

Probably. I find that solid sections like my viaduct are practically silent whereas the framed out areas are much noisier.

[Dave]

Just thinking out loud, as I am currently building some base boards, would some forms of insulation or foam/polystyrene board underneath the baseboard take any of the sound away? I'm assuming the empty space between the framework and baseboard is contributing to the noise? Or am I away off the mark?

 

Your on the money Dave, the best way to do it would be to fix the foam above the frame then the top bonded to it

[Glenderg]

Just to add a practical note here lads. If you take all the precautions of layering and putting a substrate between the board and the track, then fill it with liquid glue, the whole thing becomes a solid object and will happily conduct noise.

 

You could get a 6mm calcium silicate based board for the track bed, with a rigid insulation foam underneath (min 25mm) extending at least 25mm either side of the outside of the sleepers. Provided you kept the ballast depth to no more than 5mm in any one spot, and glued it the traditional way, you would have almost zero acoustic conductivity, I reckon.

 

[Kirley]

Here is a link to Track underlay and ballasting options:

 

http://s374444733.websitehome.co.uk/c-noise/index.htm

[Dave]

Here is a link to Track underlay and ballasting options:

 

http://s374444733.websitehome.co.uk/c-noise/index.htm

 

Good link Kieran. My method works well, a layout that I built for a client uses this method and resulted in very quiet running.

I only use PU foam (closed cell) which means glue can't absorb into it therefore the foam is glued down to the baseboard and the track glued to it and the foam becomes a excellent insulator between the two surfaces. Then the ballast is kept away from the baseboard resulting in quiet running.

It's a simple method that works!

[David Holman]

I have always laid my track on cork. I use the 3mm thick floor tiles, sold in DIY emporia. They enable you to create the all important ballast shoulder for main lines, while in stations I simply cover the whole area. Once upon a time, self-adhesive ones could be bought, which helped with the laying, but these days it is usually a case to out with the PVA glue and pin them down firmly while it dries.

As others have indicated, the amount of sound insulation is limited and it is doubtful whether cork offers any improvement to running quality. However, working in 7mm scale, I do not find my models are noisy, despite being heavy and often all metal. Equally, Arigna Town is a branch terminus, so does not have the effect of a long train running round a circuit, where I guess the noise can build up considerably. On my last branch terminus, I used Tortoise point motors and the hum from these far outweighed the noise of a train; yet out at exhibitions, the points motor noise was rarely heard above the background noise...

[Noel]

Has anybody achieved good results using 50/50% mix of copydex and water to ballast track instead of PVA?

 

i.e. Applied wet over track and ballast after track laid, not just to glue track bed to base board.