Track Underlay

[Hobby]

Brian Lambert explains it all very well and in an easy to understand way:

https://www.brian-lambert.co.uk/

[Sioned Arrowsmith]

Is this an electrofrog point issue?
If so if you like, just post the track diagram on here and we can help you.

Thank you, but no, it's a mess of automated module IR sensors and a point motor which is either too stiff for the module's built-in CDU, or so sensitive that it's bouncing.

[B.Meldon]

Is this an electrofrog point issue?
If so if you like, just post the track diagram on here and we can help you.

Thank you, but no, it's a mess of automated module IR sensors and a point motor which is either too stiff for the module's built-in CDU, or so sensitive that it's bouncing.

As someone once said, the more complcated the plumbing the easier it is to bung up the works!

Brian Meldon

[Stephen Rainsbury]

I have seen several YouTube videos where builders have laid track on polystyrene slabs, I like the idea but there was one area where they didn't agree,  One chap just painted the polystyrene, glued his track to it, then ballasted it, another one put down cork, somebody even used corrugated cardboard while others put down strips of wood, either hardboard, ply or balsa.
All of the videos were for 00 and I am not sure how well they will transfer to 009, so does anybody have experience of these methods that they could share please?

[Hobby]

The question people should ask is "do you need to raise the level of the track?". If yes then use if, if no then don't. There is no other reason for using underlay. For most 009 layouts there is really no reason to use the stuff, as most track is at ground level anyhow in real life and doesn't have a thick layer of ballast. If you use point rodding it can be set into a groove in the baseboard easily enough. But go ahead and use it if you want, it's cheap enough off eBay.

[Stephen Rainsbury]

The question people should ask is "do you need to raise the level of the track?". If yes then use if, if no then don't. There is no other reason for using underlay...

Thanks, I put that badly, I was thinking more about laying track on polystyrene. Would some kind of substrate help keep the track flatter and give something for pins to grip?

I was going to experiment with using hanging basket liner almost right up to the track to make the area look overgrown so I have a few mm to play with there.

[JulienW]

I have seen several YouTube videos where builders have laid track on polystyrene slabs, I like the idea but there was one area where they didn't agree,  One chap just painted the polystyrene, glued his track to it, then ballasted it, another one put down cork, somebody even used corrugated cardboard while others put down strips of wood, either hardboard, ply or balsa.
All of the videos were for 00 and I am not sure how well they will transfer to 009, so does anybody have experience of these methods that they could share please?

Personally there are a number of reasons that any modeller may want to use some form of underlay below their track:
Aesthetic - creates a ballast shoulder (as Hobby suggests)
Gives a space below the track - as Hobby and others have suggested if you are using 'wire-in-tube' for point operation then an underlay is probably easier to cut than the top of the baseboard to make a route for the system.
Smoothing - underlay creates a smooth surface to lay the track on.
Sound deadening - The right underlay can acoustically decouple the trains from the 'sounding board' base board.

To come back specifically to polystyrene slabs - I assume that this is the blue or pink polystyrene foam rather than the white expanded polystyrene (though some of my comments can apply to the latter) - it is a material that doesn't 'hold' fixings - track pins for example - very well, and there is probably a need to fix something to the polystyrene with an adhesive, like wood or card, to give a firm flat smooth surface on which to lay the track. The foam is also not too resilient (it is easily damaged) so afaik the usual practice is to reinforce the edges of the foam board with another material - think ply or card - and I can imagine that the same thinking would lead someone to do the same with the track bed (and any road surfaces in the landscape) - essentially making the baseboard a very lightweight frame of sides, ends and track bed held together with the foam board (carved to give the landscape). From meory I think that is how Gordon Gravett constructed his French meter-gauge layout "Pempoule"

At the moment the pin / blue foams are a new(ish) material when it comes to building layouts so there isn't an 'accepted standard' when it comes to using the stuff - hence multiple (and conflicting?) advice on the interwebby. Your best bet - if you can get the stuff - would be to make a small test piece layout to see what works best for you.

[Hobby]

Aesthetic - creates a ballast shoulder (as Hobby suggests)
Gives a space below the track - as Hobby and others have suggested if you are using 'wire-in-tube' for point operation then an underlay is probably easier to cut than the top of the baseboard to make a route for the system.
Smoothing - underlay creates a smooth surface to lay the track on.
Sound deadening - The right underlay can acoustically decouple the trains from the 'sounding board' base board.

I agree with you Julien that those are the reasons people use it however I was trying to point out that it's not necessary as some people seem to think it is.

1. Yes it gives a ballast shoulder and why I am using it this time on Ostrovia, but if you look at photos of most British NG it tends to be at ground level so using it would make it too high.
2. Wire in tube or similar, if you use plywood as the baseboard you can cut a small groove in the top layer of wood just as easily as cutting a groove in ballast.
3. Smoothing - I would hope that this is not necessary, if you choose your baseboard wood carefully and brace it properly it will be flat and not need something to smooth it!
4. Sound deadening - I've always found that if you ballast with granite and PVA then any amount of cork underlay makes little difference, the issue is the baseboard "soundbox" rather than the track and that's what needs to be addressed.

I'm NOT saying don't use it, I myself use it sometimes. But what i am saying is that it's not a prerequisite as some people seem to imply it is. If it serves a purpose then use it but you don't have to!

[Graeme Dunbar]

Other underlay possibilities:

"cork replacement" foam - dark grey or black foam of about the same thickness as cork underlay. It comes in rolls of strip (Woodland Scenics, I think) but I bought it in sheet form (about A0 size).

Camping/yoga mat - similar consistency, but much thicker. A friend recommended it and it may be great for large scales and it may work for topping the whole of a baseboard but it did not work for me, cutting to track base width. Far to fiddly to cut neatly and all the track is on a low embankment. The camping/climbing shop was was having a sale and it came in good subdued earthy colours.

The thin foam by contrast is easy to cut with scissors or craft knife. I made the mistake initially of using carpet tape to fix it both to the baseboard and the track. It "grabbed" like anything making adjustment impossible and left overnight the track and underlay started to lift.

An impulse buy at a MR Show many years ago was a sort of black mastic track underlay. It claimed that it was possible to sink the track into it and then press ballast into it, even to be able to use it built up around the track to impress cobbles or setts into. I didn't really get on with it. The seller had only OO/H0 width and I ended up with a mess trying to cut it half length-ways.

I am inclined to try no underlay next time. I've heard of people using artist's acrylic medium that dries to a slightly rubbery consistency for fixing track and that sounds attractive.

[Stephen Rainsbury]

To come back specifically to polystyrene slabs - I assume that this is the blue or pink polystyrene foam rather than the white expanded polystyrene (though some of my comments can apply to the latter)
Yes its the latter :)  I used to help kids make Warhammer scenery at school. This was made from polystrene scraps, covered either on our own mod-roc (PVA, plaster, water and cheap calico from the market), coated in B&Q vinyl emulsion (colored with whatever we could nick from Art) mixed with fine sand. This could be Ice, Red Mars, green earth (using green scatter material) and was so hard it could take the skin off your knuckles, so should be fine on my railway

it is a material that doesn't 'hold' fixings - track pins for example - very well, and there is probably a need to fix something to the polystyrene with an adhesive, like wood or card, to give a firm flat smooth surface on which to lay the track.
That's why I was thinking cork, it won'd mind getting wet during ballasting

The foam is also not too resilient (it is easily damaged) so afaik the usual practice is to reinforce the edges of the foam board with another material - think ply or card - and I can imagine that the same thinking would lead someone to do the same with the track bed (and any road surfaces in the landscape) - essentially making the baseboard a very lightweight frame of sides, ends and track bed held together with the foam board.
This is a very small test layout, just an inglenook, for me to experiment on, built on a piece of old shelving 19"x10". The frame will be external, a bit like a tea tray so the foam will under the lip at all points.

Thanks, that has helped clarify my thoughts no end, I have a plan now.  This is a big learning curve at the moment, which I am enjoying but I would rater avoid the easy mistakes if possible as it is freezing cold and horrible in garage so the sooner I can finish the messy stuff and bring it in for track laying etc the better :)

[Stephen Rainsbury]

1. Yes it gives a ballast shoulder and why I am using it this time on Ostrovia, but if you look at photos of most British NG it tends to be at ground level so using it would make it too high.
I agree completely, I couldn't work out at first why people used it, most NG railways I have visited only seem to have had a nodding acquaintance to the stuff, so why build it up. But then most YouTube videos and standard gauge.   

2. Wire in tube or similar, if you use plywood as the baseboard you can cut a small groove in the top layer of wood just as easily as cutting a groove in ballast.
This test layout is an inglenook, I was planning to use wire and tube to a pair of R/C servos hidden in a small building, so that would help

3. Smoothing - I would hope that this is not necessary, if you choose your baseboard wood carefully and brace it properly it will be flat and not need something to smooth it!
Normally this would be fine, but I want to make it look like a hill side so the track will be on 1" of polystyrene, which will have pits dug into it. I was thinking give it a coat of vinyl emulsion first, then a strip of cork to make sure its smooth. Either that or balsa.

4. Sound deadening - I've always found that if you ballast with granite and PVA then any amount of cork underlay makes little difference, the issue is the baseboard "soundbox" rather than the track and that's what needs to be addressed.
This is very small an 18"x9" plank, so shouldn't be n issue :-)

I'm NOT saying don't use it, I myself use it sometimes. But what i am saying is that it's not a prerequisite as some people seem to imply it is. If it serves a purpose then use it but you don't have to!

Thanks, that has re-enforced my ideas. I am pretty clear what I need to do now.

Stephen

[Stephen Rainsbury]

I am inclined to try no underlay next time. I've heard of people using artist's acrylic medium that dries to a slightly rubbery consistency for fixing track and that sounds attractive.

That's that sounds like another list of things to avoid. Thanks.

Another one that interested me was an Aussie guy (at least I think he was Aussie) who made up a mix of PVA, Tetrion and pumice, he laid that out in long thin strips then pushed his track down into it, so fixing and ballasting in one step. The track was kept still while it dried by dressmaking pins pushed through holes drilled in the sleepers. As soon as I can find the link I will post it.

[Hobby]

One thing you can do is cover the whole board with the stuff, that way you will keep the "ground level" look.

[Stephen Rainsbury]

One thing you can do is cover the whole board with the stuff, that way you will keep the "ground level" look.

That's a good shout. Thanks
Stephen