SP Jawbone Branch (Part 54) - Roadbed & Rough Scenery for Owenyo#3 (Aug 31-Sept 6)

Since my last post around the end of August, I've been continuing to make steady progress on Owenyo Module #3, which is the western most section of Owenyo. 

Mostly I've just been carefully pushing along the logical steps required to get each section done that won't block in or jump ahead of other steps, while keeping the maximum flexibility on the aspects that I still might want to have changes as I get to them.  The changes come in the exact positioning and height relative to the main line for the roadbed under where the transfer trestle will be going.

In this post, I'll get the blog caught up about half way to where the module is now as of the 18th of September, 2024.

I'll be going by construction dates in this post.

Aug 31, 2024

Looking Eastward and figuring where the Ballast-Deck Bridge will go.

While I put down what I expected to be the western yard switches several years ago, I've not actually wanted to place and glue the switch ties in place until I sort out the factors that need to work back onto Owenyo #2 Module from the #3 Module, including if I need to sand the top surfaces to be smooth.

SP 2850 with marks for options for Deck Bridge.

The foam was filled in with multiple pieces, including a couple of narrower strips patching over the front frame structure, cutting under the SP 2850 in the photo above.  The front edge MDF strip is actually nearly level with the roadbed, which is too high, so as I started Surforming down the foam, I ended up needing to use the saber-saw it down to form.

A somewhat southward-looking view of the mainline and trestle.

At this point, I cut out both proposed deck bridge down to the expected ground level... so I could evaluate both options against the prototype photos.  I decided that the eastern option would work best.

Looking westward out of Owenyo, and seeing how the trestle will align with the axis of the yard.

The middle yard track should align with about where the transition section of the trestle is to be located.

A lower view of the same.

As the paper elevation drawing is on the back side of the trestle, the transition section appears to be to the left of where it should be.  So this alignment of the trestle roadbed should work out about as well as the compression will allow.

The reverse angle of Owenyo Yard from the transition section of the dump trestle.

I layed in some loose bits of flex track to ponder the mainline route into the yard, just to mockup how this will look when it's done.

SP 2850 comparing the depth of the trestle-spur.

When I built the frame members into this module, I purposely made them level with each other and lower than needed to support the 1/4" MDF of the Trestle Spur roadbed.  This allows for shims to be put under the roadbed at this stage in the construction.

Last of my mock-up and playing with the static trains.

So now the questions become... How deep should the roadbed be placed?  How deep should the scenery foam make it appear... should the foam come above the mainline roadbed?  The selective compression to the shape of the spur, restricts how much space there is between the main and spur compared to the prototype acreage.

Time For Some Perspective

This process requires lots of viewing from various angles, visualizing how the foam will be fitted and formed.

In most of these photos, I'm checking the view-lines across the main track, down into the spur pit, the proportion of the trestle visible above the profile of the main track grade.

There's not much more to say about the following photos here, other than to show all the angles I evaluated these aspects from.

High angle view of whole area.

I even started pulling back and taking these photos from other angles, not usually viewed.

A view of the roughed in foam, glued in place.

I started gluing the foam in and used paper-towels on the lower staging yard to prevent any glue drips from fouling the tracks.  This worked about 99% of the time.  I did find one annoyingly stubborn drip that landed on one of the rails of the switch on the second track.  I eventually popped the glue off the rail and mostly cleared the tie with only minimal damage to the switch tie.

The tail of the spur roadbed does land against the rear frame structure.

My estimate of the depth of the trestle track pit should result in the floor of the GS gondolas being at about median ground level.  Unfortunately, the alignment of what I can place in this module is requiring the trestle to be a bit closer at the narrowest point, shifting it much farther east, compressed to the left than the prototype, and also having much more angle change of the main track on a much tighter radius than the prototype.  So all of this ends up being a compromise, and how much of the 'flavor' can I get to match photos.

Lower angle view.

Unfortunately at this point, I only have the early prototype 3d print of the Dump Trestle from late 2023.  I still need to do the updates to that drawing that I planned 9 months ago, but my hand injury prevented me from working on CAD drawings for many months.  So everything I'm doing here will be with the older test print.

Originally, I was hoping to have the spur level, but the main-track is still climbing on a 1.25% grade, so by the stub-end of the spur, it would be over 12-18" deeper than at the western end of the trestle.  I decided that because the trestle spur should be more level with the median land forms around it, I would have to put the trestle on a nearly 1% grade.  

Sept 1, 2024

As I'm a night-owl... the concept of a "new day" starting at midnight for the camera doesn't translate to my construction reality very well in telling this story, as many of these "next day" were actually just continuing past the clock hands being vertical.

Mounting the Foam

The rough foam placement along the front side of the roadbed.

I stopped at the front frame and the roadbed.  This left the last section between that and the spline sub-roadbed to fill in.  Around here I stopped, and came back the next evening after the glue had dried.

Nice to see it coming together.

Notice that I put down paper-towels to catch the Gorilla Glue drips from gluing in the foam to the spline sub-roadbed and front curved strip.

Clamping the main track roadbed sheet to the top of the sub-roadbed spline.

I roughed the foam up a bit, shaping it down to the contour of the front curved MDF strip, however the strip was actually too high.

Watching as the Gorilla Glue expands and swells up between the curved front strip and the foam.

At this point I'm actually considering changing exactly what the position and angle of the trestle-spur will be.

...Midnight...

Foam roughed-in.

Since Part 53, I've been working on roughing out the pink-foam sub-scenery form and test fitting the roadbed strip to the top of the spline.  The edges of the roadbed have been sanded, so as to provide the rough shape of the roadbed.  

 The ballast-deck trestle provisions in the left side of this photo.

On "classical" layout constructions this would be done with the 'cork' roadbed strips.  However, on this layout the hand layed and spiked turnouts require a firmer roadbed than the spongy cork will provide.  I'm not too worried about sound or drumming of the layout top, as I'm familiar with layouts that used 1/4" pine spline strip laminated in-place roadbed, and there's no issues with sound.

The reverse angle showing the foam blended to shape with the Module #2 form.

Around this photo, I burrowed out the trestle from the sub-roadbed.

I couldn't get the saber-saw in the module to notch it for the trestle opening.  So I used the electric drill with about 3/16" bit to bore-out multiple holes, then broke out the sections of Masonite with pliers.  A rasp and mill-file was used to clean it out and get it properly shaped.  The earlier spacer blocks ended up landing at this location, so I didn't have to fill in any extra material between the Masonite spline strips.

The western end of the module in the roughed condition.

Sept 6, 2024

Owenyo #3 Roadbed glued and clamped, plus weights

I threw the kitchen sink in when I was gluing down the roadbed top sheet.  I didn't have enough clamps, so I grabbed anything else "heavy" around the shop to help hold it down and in place.

Right end of the module with roadbed glued and clamped, plus weights

The glue bottle and middle bar-clamp is where I have some issues below... but when I was bonding it and setting up the clamps, I didn't know that those sections were slightly twisting.  At a certain point with any of these construction projects is a informed bet that the step will pay off, but there's always the chance that something won't be as good as expected.  I believe that the mitigation of these risks is to have anything that can "go wrong" be in a limited nature.  Keep that "something" to be an issue that is "easy" to fix later.  Try to prevent anything catastrophic from happening. - No fire, no boom!

Fixing Cross-Grade Level?

Edit: I should also note that at this point, I carved a slope into the foam in front of the main track, which ended up being about 1/4" lower than the front edge MDF scenery form.  The scenery form edge was actually nearly the same height as the track, which is too high.  So I marked it with a red Sharpie, and then cut the angle to match the foam with the saber-saw, held at a slight angle, so as to not cut the foam.  A sharp-eyed reader can see this red mark from here on over the next several posts.

After I bonded the roadbed to the spline sub-roadbed, I went through and checked the cross-level of the roadbed.  Finding a section that was subtly twisted by about 1/16" out of cross-level.  I don't want any super elevation, as this curve is only about 60-70 car lengths from the end of the branch, no one's going to be going "fast" through this curve.

In fact, this out-of-cross-level is actually a reverse-super-elevation!  So that definitely needs to be fixed.  I eventually fix this with an electric hand-sander.  I'm using the large level to do this, a 6 or 9" hand-level would be easier, but it works.

This point I'm showing how I was checking the 1.25% grade with a level, and a set point and height block, in this case a 1/4" block.  The grade ends up being pretty consistent.

On to Mocking Up Spur

In the previous photos, I was using shims of between 1/4" and 3/16" under the spur roadbed.

At this point, I removed the trestle spur to start working out the height shimming.

Notice that at this point the trestle spur and trestle mock-up are rising.  They're in the same X,Y position, but are just being shimmed up vertically.

Note the roughed up foam, but not the red mark after I lowered the front edge.

Mocking everything up in place again.  

Edit: This photo above is actually slightly out of order, as the front edge of the module hasn't been lowered yet.  See previous edit above.  The photo below shows clearly the difference.

In Closing

I'll leave it here for now.  This is only catching up about half-way to where the layout is now.  For now I'll show a sneak-peek of how the module looks today on Sept 17, 2024.

Photo from 2024-09-15, after installing the Trestle Spur, which I'll cover in detail in Part 55.

I've also made the decision that I will not be getting the Owenyo section of the layout operational for the SPH&TS Convention in Sparks this year.  Between my hand injury putting me out of commission to be able to work on the layout for more than six months of the last year, and other commitments in the next month.  I'd rather not rush the construction to get a "short term gain", but compromise on the long term goal of getting the layout built in the best way I can build it.

Jason Hill

Related Articles:

Jawbone Branch Layout Build Index - See all postings in this series from this linked page.

SP Jawbone Branch (Part 53) - Curved Spline Sub-Roadbed for Owenyo#3 - Previous post in the series