Laying Track on Foam

[Challenger]

I recently dismantled and removed my 1st HO layout and am planning to rebuild it with modifications to the benchwork based on lessons learned from that first layout. Attached is a photo from the 1st layout. For my 2nd layout, I plan to attach track directly to foam. No cork roadbed. My plan is this: Screw 1/4" plywood to the top of the open-grid benchwork. Glue a sheet of 1" foam core insulation on top of the 1/4" plywood. Finally, glue a 2nd sheet of 1/4" plywood on top of the foam core. Glue and spike the track to the top layer of plywood. This is my reasoning: (1) I used 3/4" plywood as the base of my 1st layout. Overkill. I want my 2nd layout to be as lightweight as possible while at the same time providing a solid base. (2) I am adding the 1/4" plywood on top of the foam because I am afraid that spiking ties directly to the foam could compress the foam, causing undulations. (3) When spiking the track to the top layer of plywood, I plan to drill a pilot hole through the tie, spike the tie and then add a small drop of super glue to the top of the spike. One of my concerns has to do with glueing the top layer of plywood to the foam core. I'm not sure I trust that the plywood won't separate from the foam core over time. How can I address that concern? Does my plan make any sense at all? Am I overthinking this? Any thoughts, concerns, suggestions will be greatly appreciated. Thanks in advance.

 

[ctclibby]

I recently dismantled and removed my 1st HO layout and am planning to rebuild it with modifications to the benchwork based on lessons learned from that first layout. Attached is a photo from the 1st layout. For my 2nd layout, I plan to attach track directly to foam. No cork roadbed. My plan is this: Screw 1/4" plywood to the top of the open-grid benchwork. Glue a sheet of 1" foam core insulation on top of the 1/4" plywood. Finally, glue a 2nd sheet of 1/4" plywood on top of the foam core. Glue and spike the track to the top layer of plywood. This is my reasoning: (1) I used 3/4" plywood as the base of my 1st layout. Overkill. I want my 2nd layout to be as lightweight as possible while at the same time providing a solid base. (2) I am adding the 1/4" plywood on top of the foam because I am afraid that spiking ties directly to the foam could compress the foam, causing undulations. (3) When spiking the track to the top layer of plywood, I plan to drill a pilot hole through the tie, spike the tie and then add a small drop of super glue to the top of the spike. One of my concerns has to do with glueing the top layer of plywood to the foam core. I'm not sure I trust that the plywood won't separate from the foam core over time. How can I address that concern? Does my plan make any sense at all? Am I overthinking this? Any thoughts, concerns, suggestions will be greatly appreciated. Thanks in advance.

Challenging isn't it! Anyway, suspect you are going the correct way as far as I know spikes will not hold in foam. I contemplated sandwiching foam between to sheets but decided I was not going to do that and just use Foam with Ply on top. The whole shebang is on 12" center 1x2" joists. I would still stick with cork for the roadbed. Consensus is Foam is a sounding board and could get pretty loud.

Laminating Foam to Ply should not be a big deal: Flat place, good construction adhesive that does not eat Foam; weight it down for 12/24 hours. I tested and I could stand on the Lam with 1 foot each side of a joist. Well it did bend a touch, but I do not have any 200Lb engines or cars so pretty much moot.

L8r

 

[logandsawman]

Well, you asked...my opinion is foam sheets are entirely unnecessary.

From what I can understand, they are used for one reason, they are easy to make holes in .

I am well aware of how universally they are used in model railroading. And, there is no one way to make a layout. But, I am certain landfills can be filled with all the foam discarded from defunct model railroads .

Dave LASM

 

[Challenger]

Challenging isn't it! Anyway, suspect you are going the correct way as far as I know spikes will not hold in foam. I contemplated sandwiching foam between to sheets but decided I was not going to do that and just use Foam with Ply on top. The whole shebang is on 12" center 1x2" joists. I would still stick with cork for the roadbed. Consensus is Foam is a sounding board and could get pretty loud.

Laminating Foam to Ply should not be a big deal: Flat place, good construction adhesive that does not eat Foam; weight it down for 12/24 hours. I tested and I could stand on the Lam with 1 foot each side of a joist. Well it did bend a touch, but I do not have any 200Lb engines or cars so pretty much moot.

L8r

Thanks for your reply. I've thought about the sound and am ok with that. Thanks for sharing your experience with laminating foam to ply. I am encourged.

 

[Challenger]

Well, you asked...my opinion is foam sheets are entirely unnecessary.

From what I can understand, they are used for one reason, they are easy to make holes in .

I am well aware of how universally they are used in model railroading. And, there is no one way to make a layout. But, I am certain landfills can be filled with all the foam discarded from defunct model railroads .

Dave LASM

Dave, thanks for your thoughts.

 

[RhB Michael]

I agree with Dave. If you are laying track on plywood the foam is an unnecessary expense and additional weight you are trying to avoid.

 

[NVSrr1500]

The ply will separate from the foam. and whole bunch of other headaches. The 3/4 inch ply was a good one allowing for almost no bench work. half inch only needs a little more bench work. Foam and quarter inch ply needs a good amount of bench work to support it the ply sags over time and the foam is fragile and needs alot of support. As recently demonstrated, foam is a large deadly fire hazard. and you don't need super glue. a pilot hole is a good idea. the hole needs to be 2/3 the nail size. that goes for any pilot hole for any screw or nail size. keep this in mind too. The thinner the ply. the more bench work construction needed to keep the layout ridgid and square and stable.

 

[NVSrr1500]

Well, you asked...my opinion is foam sheets are entirely unnecessary.

From what I can understand, they are used for one reason, they are easy to make holes in .

I am well aware of how universally they are used in model railroading. And, there is no one way to make a layout. But, I am certain landfills can be filled with all the foam discarded from defunct model railroads .

Dave LASM

don't forget the deadly fire hazard of foam.

 

[Challenger]

I agree with Dave. If you are laying track on plywood the foam is an unnecessary expense and additional weight you are trying to avoid.

The ply will separate from the foam. and whole bunch of other headaches. The 3/4 inch ply was a good one allowing for almost no bench work. half inch only needs a little more bench work. Foam and quarter inch ply needs a good amount of bench work to support it the ply sags over time and the foam is fragile and needs alot of support. As recently demonstrated, foam is a large deadly fire hazard. and you don't need super glue. a pilot hole is a good idea. the hole needs to be 2/3 the nail size. that goes for any pilot hole for any screw or nail size. keep this in mind too. The thinner the ply. the more bench work construction needed to keep the layout ridgid and square and stable.

Thanks for your reply. Very helpful as I think this through. Especially "The thinner the ply, the more bench work construction needed to keep the layout rigid and square and stable." You reminded me that when it comes to benchwork, objective #1 is to ensure the layout is rigid, square and stable. I lost sight of that. I was too focused on weight. I'll be 79 next month. Someday, me or someone else is going to have to dismantle and remove this layout. I didn't want whoever that is to have to deal with large sheets of 3/4" plywood and 2x4s. Anyway ... If I use 1/2" plywood and joists every 2' on my HO layout, do you think that will be adequate? I understand that the quality of the ply and the proper use of bracing are also going

I agree with Dave. If you are laying track on plywood the foam is an unnecessary expense and additional weight you are trying to avoid.

I'm thinking you're right about that.

 

[Challenger]

To finish my reply to NVSrr1500 --- I understand that the quality of the ply and the proper use of bracing are also going to affect whether the layout is rigid, square and stable. Do you (or others on this forum) think that 1/2 ply and 1x3 joists every 2' on an HO layout will be adequate? Thanks.

 

[ctclibby]

Challenger: You are probably good to go. Because ima lazy, I do 12" centers as it is easier for me to remember grades: ~1% is 1/8" rise and I don't have to get the calculator helper out. Only costs 3 more joists considering 16ft run. Price wise, you might consider OSB - stronger across the horizontal span because it is more dense but does have issues; ya need to seal it top, bottom and 6 edges. 1/2"x4'x8' was ~$10 ( last week ); Plywood is 3 or 4 times that of which also should be sealed. Although many do not seal ply.

Have fun!

L8r

 

[RhB Michael]

1/2" plywood is fine for benchtop use. The framing members size is sort of a 'depends'. I used 1x4 because I wanted the rigidity and strength for climbing on top of the table during construction and track laying. Most are spaced on 24" centers except where an access opening was needed and then the spacing was a little wider in that section.

If you don't need the rigidity or strength for climbing, then I think 1x3 is fine. Seems a little rickety to me, and the cost is nearly the same for 1x4, but it will work. If you weigh more than about 200-225 I woudn't trust 1x3 for climbing.

 

[santafewillie]

To finish my reply to NVSrr1500 --- I understand that the quality of the ply and the proper use of bracing are also going to affect whether the layout is rigid, square and stable. Do you (or others on this forum) think that 1/2 ply and 1x3 joists every 2' on an HO layout will be adequate? Thanks.

Yes, it will be stable. But I would put a joist every 16" instead of every 2'. I used 1"x4" because that's what I had available. I agree with skipping the foam.

 

[Challenger]

Challenger: You are probably good to go. Because ima lazy, I do 12" centers as it is easier for me to remember grades: ~1% is 1/8" rise and I don't have to get the calculator helper out. Only costs 3 more joists considering 16ft run. Price wise, you might consider OSB - stronger across the horizontal span because it is more dense but does have issues; ya need to seal it top, bottom and 6 edges. 1/2"x4'x8' was ~$10 ( last week ); Plywood is 3 or 4 times that of which also should be sealed. Although many do not seal ply.

Have fun!

L8r

I love everything about this hobby. Sorry, but I'm not buying the lazy part! The 12" centers sounds smart to me. I sure wouldn't have been smart enough to come up with that. Thank you!

 

[Marlin39]

I used foam for the last 3 layouts and then switched to 1/4" plywood with 1/4" cork sheet on top for my current one. It was a whole lot easier to attach stuff to cork than foam.

Just my .02.

 

[Challenger]

Yes, it will be stable. But I would put a joist every 16" instead of every 2'. I used 1"x4" because that's what I had available. I agree with skipping the foam.

Thanks - I may end up taking your advice and go with 16". My wife and I have talked about downsizing and finding a place where the bedroom is on the first floor and I don't have 2 acres to mow. In other words, talking about moving at some point. Neither of us wants to but it could happen. I haven't shared the following aspect of my plan on this forum because I know that other model railroaders will think I'm crazy. And they would be right to think that. What I'm thinking is this - build this 6' x 16' layout in 8 separate sections and attach the 8 sections with dry wall screws. Each section would be 3' x 4' and have its own top. Why? Two reasons: (1) I can separate the eight sections, remove the legs, carry everything by myself and fit it in the back of our Subaru Outback. That's the theory, anyway. A lot of work I suppose and more than 1 trip in the Subaru; and (2) if we do move, this gives me some flexibility (maybe I'll only have room for a 6x12 layout). If I go, the benchwork goes with me. Not sure if they make coffins that big, but I'll deal with that later.

 

[Challenger]

I used foam for the last 3 layouts and then switched to 1/4" plywood with 1/4" cork sheet on top for my current one. It was a whole lot easier to attach stuff to cork than foam.

Just my .02.

So many different ways to approach this. Thanks for sharing yours!

 

[Challenger]

I agree with Dave. If you are laying track on plywood the foam is an unnecessary expense and additional weight you are trying to avoid.

That makes sense. Thanks!

 

[migalyto]

I know that other model railroaders will think I'm crazy. And they would be right to think that. What I'm thinking is this - build this 6' x 16' layout in 8 separate sections and attach the 8 sections with dry wall screws. Each section would be 3' x 4' and have its own top.

Don't think that is crazy at all! Very smart!

Many times we see model railroads thrown in the dumpster due to not being able to be moved easily if they have too.

 

[RhB Michael]

They will have to cut mine out of the room after I've left this world. It is all screwed and glued. It is also screwed to the wall studs where it was possible. It is rock-solid and there is absolutely no movement.