Track underlay thickness

[barney121e]

What thickness underlay would people suggest for a OO gauge layout?

 

Cheers

 

[Miss Prism]

That depends on what you expect underlay to do.

[DCB]

You can use underlay for sound deadening if you have built a baseboard which resonates, but it's better to build a baseboard which doesn't resonate in the first place. You can use it to replicate ballast.   Off the shelf underlay likes nice warm dry conditions, it disintegrates if it doesn't like the conditions .  I bought a lot of Peco track very cheaply from an abandoned layout as it  had been pinned down using Peco underlay which had rotted and let the track go dog legged and hang loosely on the pins.    You are probably better off with cork ballast on a permanent layout but off the shelf underlay should be fine for a temporary layout planned for three years or so, as it should facilitate removing the track when the layout reaches the end of its life.

[barney121e]

6 hours ago, DCB said:

You can use underlay for sound deadening if you have built a baseboard which resonates, but it's better to build a baseboard which doesn't resonate in the first place. You can use it to replicate ballast.   Off the shelf underlay likes nice warm dry conditions, it disintegrates if it doesn't like the conditions .  I bought a lot of Peco track very cheaply from an abandoned layout as it  had been pinned down using Peco underlay which had rotted and let the track go dog legged and hang loosely on the pins.    You are probably better off with cork ballast on a permanent layout but off the shelf underlay should be fine for a temporary layout planned for three years or so, as it should facilitate removing the track when the layout reaches the end of its life.

 

13 hours ago, Miss Prism said:

That depends on what you expect underlay to do.

I was under the impression that underlay helped form the shoulder for ballast, am i right?

[DCB]

It does look like a ballast shoulder, IMHO  when new the grey is not a bad match for granite ballast track with Meldon quarry ballast of the late 1960s but today's  2010(?) on ballast looks a lot more red / brown.  I find underlay gets dirty and goes black which isn't good.  The ballast varies from very thin but laid right over the top of the sleepers late 1890s, increasing  to several feet thick on the Western Region in the HST era 1975 on before they had to watch overhead clearances with main line electrification in the 2010s.     The Peco Streamline underlay is great for 1960 ish but you need more like 12mm for HST era, and it's just plain wrong for 1890.

Edited June 26, 2022 by DCB

[MyRule1]

Although the RMWeb search facility is not that good, a very week used search engine came up with this thread from 12 years ago

 

although the initial question is different  the   thread does widen.

[Philou]

The depth of ballast on the 1:1 railway will vary usually between 150mm - 250mm, the latter used under concrete sleepers. If you're representing a goods yard or MPD (especially steam), then there is unlikely to be much visible ballast and therefore no need to underlay - unless you want soundproofing.

 

Therefore, 2 or 3mm cork chamfered both sides should be plenty high enough to represent the ballast. I use the green fibre carpet underlay as its 2mm thick and can be cut to a chamfer. The downside is that it dulls cutter blades fairly quickly.

 

As @DCB says, for prototype high speed applications, the ballast will be deeper.

 

Top tip for me is to use suitably sifted coarse builders' sand to represent the stone size of 1/2" to 3 1/2" and then coloured once in place as, unfortunately, suitable granite/limestone is not readily available here.

 

Cheers,

 

Philip

Edited June 26, 2022 by Philou

[brossard]

I can recommend this stuff:

 

https://www.hattons.co.uk/stocklist/1000484/1000588/1000678/0/woodland_scenics_oo_gauge_1_76_scale_track_underlay/prodlist

 

Closed cell foam.  I have used the 0 gauge version on my layout and it really works well.

 

 

Combined with tacky glue for fixing the foam and track it provides for well damped track.

 

Another side effect I discovered last weekend when I debuted the layout at a show.  During assembly something slipped and two lengths of track came unstuck.  My heart sank but on inspection, it was an easy repair to simply put some PVA down and reposition.  The thing about tacky glue is that it sticks track but doesn't form rock hard when dry but stays flexible.  Therefore, thankfully the rail didn't unzip.

 

John

[barney121e]

4 hours ago, brossard said:

I can recommend this stuff:

 

https://www.hattons.co.uk/stocklist/1000484/1000588/1000678/0/woodland_scenics_oo_gauge_1_76_scale_track_underlay/prodlist

 

Closed cell foam.  I have used the 0 gauge version on my layout and it really works well.

 

 

Combined with tacky glue for fixing the foam and track it provides for well damped track.

 

Another side effect I discovered last weekend when I debuted the layout at a show.  During assembly something slipped and two lengths of track came unstuck.  My heart sank but on inspection, it was an easy repair to simply put some PVA down and reposition.  The thing about tacky glue is that it sticks track but doesn't form rock hard when dry but stays flexible.  Therefore, thankfully the rail didn't unzip.

 

John

 

Hi John

 

Do you think sticking the track with tacky glue on a stay at home layout would be enough?

[brossard]

20 minutes ago, barney121e said:

 

Hi John

 

Do you think sticking the track with tacky glue on a stay at home layout would be enough?

 

I do, mine is mostly stay at home.  We only took it out as a proof of concept.  The layout is unlikely to be disturbed at home so not subject to the issue I had.

 

John