Jawbone Branch - Index Page

 This is my combined Index Page for all my blog posts related to researching, designing, building, and operations on my HO scale model of the Southern Pacific's "Jawbone" Branch from Mojave to Owenyo.  
January 2021 3D CAD model of my "Jawbone" Branch concept in my shop/study space.

Brief Overview of the Layout & Goals

My modeled version will focus on the northern end of the branch terminating at Owenyo with a couple of other stations north of Inyokern.  The southern part of the branch was also worked by a regular heavy transfer run out of Mojave to the Trona Rwy interchange at Searles, often handling around 50 cars with two AC-class 'cab forwards'.  I don't have the room to model Searles-Trona, nor the trains that ran there.  

Trona aerial 1941 - Tim N Lola Byrne Collection

While I would have enjoyed modeling the Trona's small fleet of engines and associated cars, the plant at Trona, which would be nearly the size of my whole space, let alone the 50-car trains.

SP 3237 switching at Bartlett circa 1950-1952 - photographer unknown Dani "Inad Akeb" Collection

No, my layout will be focused on the three-times-a-week (six day) Owenyo Local, which went all the way from Mojave, 143 miles, to Owenyo and then returned the next day.  The layout will also need to fulfill two other major goals:
  1. Provide the physical testing plant for equipment which will be placed in service at the La Mesa Club, in San Diego.  This means curve radius, easements, mainline switches, vertical curves, etc all to club specs.
  2. When sceniced, provide good photography backgrounds for various models that I'm working on. - This may also involve a section of "Flex-scenery" in front of the bookcase, where I can have a narrow section of roadbed and set up various background flats, or white/green-screen backgrounds for the photos of pilot models for OwlMtModels products.

Index of Blog Posts:

(Click on photos below to follow the link to the post)

SP Jawbone Branch (Part 1) - Concept & Design

SP Jawbone Branch (Part 2) - Researching and Changing of the Plan

SP Jawbone Branch (Part 3) - Consists and More Bartlett Research

SP Jawbone Branch (Part 4) - Freight Car Roster

Buying the materials for the benchwork

Working out the logistics for the staging yards other details.

Historic movie film clip of Owenyo Local
Starting construction of the layout
... or at least how to cut out the sections
More research materials have surfaced for my modeling of Little Lake
No More Linnie!?

Design Changes to Owenyo
Where's the Foam Going?

A deeper dive into the buildings and track arrangements.

Transfer to the SPNG?!

Cutting material
Starting to assemble layout sections

Over-stuffing Designs 
Other planning issues.

Taking the next steps in assembling the layout structure.

A closer look at historical Timetable Passenger Operations
Employe Timetable Researching and Commentary

Fabricating wall brackets
Cutting "Pits" in the top skin
Cutting complex joints for Owenyo #1 wye structure.

Upgrading Owenyo #2 with better bracing structure
Mojave Staging bracing strucutre
First Extruded Styrene Foam experience

Owenyo #1 module's removable wye construction starts
Wye Tail module test fitting of parts
MicroEngineering track and supplies arrive!

Secondary Bracing completed
Bracing and supports for wye "keel-spar" fabricated and installed

Modifications to the layout, getting closer to the photos!
Bolt Holes
Alignment Issues

Supply Train Arrives
Track Laying Tools
Track Laying Techniques
Wrapping Up the First Week of April

Details West Switch Kits
SP Track Standards
Laying Out Switch Geometry
Glue Down the Ties
Sanding Ties
Notching Ties for Rail Joiners
Heel Rails
Point & Closure Rails
Multiple Switch Alignments
Up Next
First Run! & Video

Old Lighting
New 4000-4500K LED Lighting
Evaluating Lighting
Future Lighting Upgrades

Laying Track

Engine Spot details
Wye details, Derails?, East Tail Ramp
Water Tank details

Points and Throw-Bars
Switch Point Jig
Switch Progress
SG-NG Transfer Ramp/Pit Switch
Switch to House Pocket Stub
West Wye Switch
Next Steps

I'll try to keep this page up to date on posts from the SP Jawbone Branch series as I post them.


  1. Jason,

    Are you going to use Homosote, cork, or any other sound deadening layer? If so, what are your thoughts and choices?

    1. I'm not really planning to use very much of any roadbed in Owenyo and Mojave. I may end up using some pine strips ripped to 1/4" square for spline roadbed, like we use at LMRC, which accept spikes well. LMRC uses 1/4" upson board for the yards, which accepts spikes very well too, but that material has become hard to find.


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