Thoughts on optimizing cookie cutter roadbed?

[R L Smith]

I made my helix from CNC milled MDF quarter sections.  What really helped speed up construction and made the cost if the cutting worth it was having a 1 mm deep channel milled along the curved centerline to the exact width of Atlas Code 55 flex.  Once I had all the pieces ready, curves, spacer blocks & all rail joiners prewired with feeders I was able to build up the whole thing over the weekend with screws and construction adhesive to bond the track into the groove  No waiting for anything to dry to keep centreline.
At the same time I had the same vendor cut a few sheets of MDF into perfect splines for subroadbed.

Day-um.  No long-term reliability issues there.  Nice work!!

[Angus Shops]

Most of us barely think twice about dropping a couple hundred on a new loco, so I figure spending a few more dollars than we prefer on good solid plywood is a good investment in a new layout. And I used almost every scrap of ‘off-cut’ up eventually.

[wazzou]

Most of us barely think twice about dropping a couple hundred on a new loco, so I figure spending a few more dollars than we prefer on good solid plywood is a good investment...

Agreed, I can’t like this enough. 

[CRL]

It’s not the load carrying ability of 1/4” plywood that is my concern. I’ve used even smaller door-skin plywood to form the bridge deck over a stream on an n-scale layout. Glue a couple of plate girder sides on & voila... instant bridge. It’s that a lot of 1/4” plywood doesn’t have a very stable laminate if you buy the cheaper interior grade plywood which doesn’t use a waterproof glue. Plywood made with 5 ply laminate with waterproof glue is available in 1/4” and is amazing stiff & stable. 3 ply can be twisted like a pretzel.

[mmagliaro]

It’s not the load carrying ability of 1/4” plywood that is my concern. I’ve used even smaller door-skin plywood to form the bridge deck over a stream on an n-scale layout. Glue a couple of plate girder sides on & voila... instant bridge. It’s that a lot of 1/4” plywood doesn’t have a very stable laminate if you buy the cheaper interior grade plywood which doesn’t use a waterproof glue. Plywood made with 5 ply laminate with waterproof glue is available in 1/4” and is amazing stiff & stable. 3 ply can be twisted like a pretzel.

TOTALLY AGREE... That's why I brought up using 5 ply, hardwood plywood (the maple or birch ply stuff).
And I agree, if you brace it well, 1/4" would work.   People often overbuild with heavy materials that are
no stronger or more warp-resistant.  It's just added weight.

[DKS]

Are you within a 75-minute round-trip from a Home Depot?
If so, then rent one of their trucks for $19.

Agreed. Cutting large sheets down to fit your car can lead to an increase in waste.

[Ed Kapuscinski]

But with 1/4", won't the Mantis Toboggan brand track nails go right through? 

[Sokramiketes]

1/4" Baltic Birch plywood is great stuff.  That's the top surface of Modutrak modules, where part of the design consideration is to keep them light weight. 

Now, we don't generally lay track directly on that surface.  That surface is to set the overall size of the module, and allow everything else to be built from that datum surface.  The spline roadbed is the thing that actually provides a warp free support for track.  And is a backbone of the module. 

The only spot for heavy duty material, is the 3/4" Baltic Birch at the module ends.  This is to deal with the abuse of clamping modules together, and transferring that load.

The sides, a glue laminate of 1/8" Baltic Birch plywood and 1/8" masonite fascia profile, is plenty side support to keep the whole module from sagging.  If your 1/4" ply ties into a nice tall member like 6" of masonite fascia, that can also keep it from sagging. 

Our original group of modules are coming up on 16 years and have handled the harsh life of a traveling layout even better than I could have hoped.  Now, if Super Trees were as robust...

[CRL]

Datum surface... must remember that term. Much more elegant than what I’ve been using. 

[John]

OK, so this may have been covered earlier, but you can reduce waste by going with thinner ply and layering it for the curved sections of roadbed. Cut a series of arcs for the most common radii, and overlap them like very long, skinny bricks. You should be able to get a lot of such arc segments out of a sheet of ply with little waste, then glue and laminate them together in overlapping sections to make full arcs for long curves.

Does this make any sense to anyone, or do I need to get my crayons out?

This is how I built a lot of the subroadbed on the M&O .. I cut 3/8"  or 5/16" ply to 1 1/2" width .. then used those strips to make "blocks" a few inches long .. which where then laminated together into 2 or more layers ...  then put cork roadbed on top


sorry for the crappy picture -- its the best I could get with the lighting I had -- but this is a good strong joint with just wood glue .. if you build it flat on the floor, you can also make it relatively flat

[John]

Yes, it is too thin, but on a multi-level layout where you're minimizing grades, that buys you a tad of clearance, including for hands between levels.

If you look at the post - I turned a stiffener on edge between risers wherever I could.   Just scrap lumber, but it sure helps to have an overhead radial saw (which I do) to rip up almost anything to a consistent dimension shape.

The other advantage to 1/4" is that it makes it a heck of a lot easier for under-table switch mounts, makes it lighter, and does some of the vertical curve easements rather naturally.

I think in N scale we tend to overdo the benchwork .. some of you would freak out at my wiring and carpentry .. I'm not building a house -- I want the structure to hold little trains ..

[peteski]

I think in N scale we tend to overdo the benchwork .. some of you would freak out at my wiring and carpentry .. I'm not building a house -- I want the structure to hold little trains ..

Exactly!  Like I mentioned earlier: Even 1/4"Lauan plywood works quite well for an N scale layout, and  has been stable for around 30 year so far.

[glakedylan]

1/4" birch plywood, both sides finished on 1x3" grid spaced at 16" was my layout for over 20 yrs.
never had a problem. 1x3"s handpicked at a big box store for straightness and legs with mainframe
connecting to boards together to form an "L" shape which provided significant sturdiness.
even with children bumping into it (free-standing island) it never moved enough to derail a locomotive
or any rolling stock.


used the same for HO with 3/8" plywood, in a basement without heat or dehumidifier. same results
with a layout that lasted well over 10 yrs.


that's my usual and I'm sticking to it. now, if I could finally get a dedicated space for a new one.


sincerely
Gary

[Point353]

I think in N scale we tend to overdo the benchwork .. some of you would freak out at my wiring and carpentry .. I'm not building a house -- I want the structure to hold little trains ..

However, sometimes you'll have 1:1 people leaning on your 1:160 layout.
The April issue of RMC has a brief article which includes a photo of Rapido's Jason Shron leaning (if not almost laying) on the lower level of his layout while working on some wiring on the underside of the layout's upper level.
Ed K is planning to have a two-level layout.

[John]

However, sometimes you'll have 1:1 people leaning on your 1:160 layout.
The April issue of RMC has a brief article which includes a photo of Rapido's Jason Shron leaning (if not almost laying) on the lower level of his layout while working on some wiring on the underside of the layout's upper level.
Ed K is planning to have a two-level layout.

I have a double level N also .. mostly a series of "modules"  1x4 or 2x4 and 4x4 end loops with yard areas solid plywood tops -- it's designed to move if I ever decide to leave the Peoples Republic, or easy to throw into the dumpster when my ticket gets punched.  The only place I would ever need to climb on the benchwork is around some utility lines but the 24" width makes it fairly easy to those items.