Jawbone Branch - Index Page

East Owenyo looking back into town - Andrew Brandon collection

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)

Locals out of Bakersfield
Switchers at Bakersfield
Locals out of Mojave
Mountain Work Train
The "Jawbone Branch"
Owenyo Local
Searles Turn (Mojave-Trona)
"Blitz" Local (Mojave-Palmdale/Saugus)
Switcher at Mojave

SP Jawbone Branch (Part 1) - Concept & Design
History of Stations
Rough Track Plan
To Mojave or Not to Mojave?
Engine Options
Freight Car Options

SP Jawbone Branch (Part 2) - Researching and Changing of the Plan
First couple drafts of Track Plan
Changes to Bartlett, Little Lake, Linnie options

SP Jawbone Branch (Part 3) - Consists and More Bartlett Research
California Division of Mines - Owens Lake Alkali Plants
Clark Chem Co.
Freight Traffic to Bartlett
Consist Photo Analysis

SP Jawbone Branch (Part 4) - Freight Car Roster
SP Steel GS Gondolas
UP Steel GS Gondolas
SP All-Steel Boxcars
Foreign Line Boxcars

Buying the materials for the benchwork
Doing the Deed
The Plan
Construction Plan Notes
The Cutting Plan (not exactly followed later!)

Working out the logistics for the staging yards other details.
Staging Yard - Must Have for Operation
Freight Car Fleet Size?
Conclusions about Fleet Size and Layout Capacity
What Size Mojave Staging Yard can I have?
Engineering Questions

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?!
Too bad I'm not able to model Lone Pine

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

Flashback to 2021 - reaching back for older blog drafts to post
Prototype photos of Ramp
Building the Model Ramp - Layout Top
More photos arrive from Alden Armstrong
Slight Oops - new photo shows minor laying-out issue with East Owenyo Switches
Closing Thoughts, Healing up, & Moving forward in 2022

12V DC Power Supply for LED Lighting
120V Power Cable Modifications
Dimmer Switch

Molex Connector system
Feeder Wires
Bus Wires
Plugs on 12VDC Power Supplies

Owenyo Modules
Drilling Feeders
Installing Feeders
Omega Feeder Wires
Bus Wiring
Soldering Up the Feeders
Applying "Goo"
Extra Bus Cable for DCC Throttle
Adjustments to Tracks
Interlocking Wye "Safety" Blocks
Finishing West Owenyo

Disassembly of Mockup
A Time for Bonding

Laying Out the Module
Cutting the Material

Ground Throws
Owenyo Engine Spot Cutout Switch

SP Jawbone Branch (Part 37) - Placement of NG Trestle & 1st Curve
Main Curve Alignment
Trestle Position, Size & Position
Trestle Position
Bridge Position
Next Steps - Construction of Owenyo #3 Frame & Structure

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

As of 2023, I'm posting my Jawbone Branch blogs on it's own page: Jawbone Branch Index Page.  Here's the rest of the posts since January 2023.

2024, Mar 5 - SP Jawbone Branch (Part 41) - Time for Some Pondering & Research Updates

Note: I'll also not be continuing to cross-post Jawbone Branch articles here, but instead on my Jawbone Branch blog, where I'm focusing the layout posts.  I'm also keeping a full index of all the Jawbone Branch build posts there.


  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.

  2. I was looking at your plan and a thing occurred to me. You could run the track trough the bookcase instead of in fornt of it. Box the track in above and below with shelves to make a reasonably sized space. Then paint the inside of your new space a photography friendly color. Install photo friendly lighting on the underside of the top shelf. Ta da! Instant photo set for models. You could use your flex scenery behind them as you wish. I would add a glass door for display and dust control, and I would probably leave it white for photographing the models we overhaul at Brass Mechanics. I love this idea and am going to do something similar to this.

    Cheers! Bill

    1. Thanks for the interest Bill,
      Yes, I thought about doing something like that with the book cases originally... for all of about 0.36 seconds until the longevity of the bookcases kicked in. These aren't Ikea bookcases that I can just cut holes in whilly-nilly... they're very nice family hard-wood book cases which I really don't want to deface in any way punching train holes in. So they need to stay as they are. Also there aren't many other good places for tall bookcases like them around anywhere else... so this is about as good a place for them as I can get. The step in the North Wall that they create actually works out very well to put the curve in the middle of Little Lake, so I'm happy with it.
      Yes, I'll probably set up dioramas that can go into the book cases for photos and other things.

      Thanks for the input!


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