Tuesday, May 28, 2024

SP Jawbone Branch (Part 49) - Spline Start for Owenyo 3rd Module Construction

Time to see some progress on the new module!

So since the last post, I've been working on getting the spline ready to build for the module and also cut out the top sheet of MDF a bit closer to the final shape, but I'll be covering some thoughts on that towards the end of this post.

Construction of the Main Track Roadbed Spline


1/4" MDF spline side plate with spacer.

I fashioned the level section of the new main track roadbed spline from extra side-frame material.  I kept these to only 6" long, as to the right of this point, the track will both go into the horizontal plane curve, and also be transitioning to a 1.25% down grade.

Three of the four spline sections.

Each piece was notched to catch the slots cut in the end-plate block back in Part 47.  This should form a very strong attachment, which is directly bolted to the #2 Module, to the left.  The next section of spline will have fingers that will fit between the straight and level splines now mounted.

Clamping the fourth spline plate.

The clamp was to hold the spline's spacers while the glue dried.  I was using another block and sighting across the top of this to see that it was level with the rest of the framework.  Some of the plates about 1/32" proud of the frame's top, which will be sanded down once the grade and transition spline pieces are built.  But it's a good solid starting point for now.

Wobbly Walls?


Shimming blocks in place for future backdrop.

I decided to tighten up the module's position against the walls.  I should say that the walls are actually quite a bit out of straight and square.  So I'm planning ahead now for the modules to be straight and with enough space for the backdrop sections to slide down the back edges.

Notch the Front Frame


I finished the notching of the front frame strips for the spline roadbed and Owenyo Trestle roadbed sheet.

I was able to take the framework outside and clamp it in place while I used the saber-saw to cut out the notch for the future spline roadbed support and the flat area for the Trestle roadbed to sit.  The cut's a little rough, but it should sort out with the notching and shiming that I may be putting into finalize the grade of the main track spline and spur.

Shortening the Module?!


After a week of having the module under construction, I have caught the corner of the module next to the door several times.  I also don't like that this end point for the module would mean the switch to the trestle is split across the module joint.

Marking right frame strip for shortening cut.

I measured to sort out a point where the track centers should be about 1.25" apart, which will be well clear of the switch frog.  This shortening cut was made with a saber-saw, as it was getting late at night, and I didn't want to make table saw noise outside.

The end-plate was popped off the short frame cut-off section.  This time I applied Elmer's Wood Glue this time and the pair of corner clamps until the new joint was dried.

Top Skin Testing


At several points during this series of construction, I was testing the fit of the top-sheet of MDF, which will make up the roadbed.

The trestle spur has 9 cars spotted on it for testing here.

At this point I started play with the grade profile, how much shimming is needed at the various points the skin crosses the structural supports.  Yes, I'll still have to account for the spline support under the skin as well, but I want to rough out how the grade profile will work out.

Better view of the end of the top skin, which will be shortened.

I'll probably set up a 1.25% grade block for my bubble-level, so that I can account for the grade on the curve, and be sure that it works out correctly. - Hopefully, I don't have to cut into the end-plate block or move it... again!


Ballast Deck Trestle?


Owenyo Trestle Jack Sims Photos - TJ Huebner collection-F

I also want to have the small ballast-deck trestle on the main track.  The drainage of which is supposed to pass under the grade section of the trestle, which will be mostly in the backdrop.  This creates a left-right offset of the details on the main track and where the trestle is positioned.

Possible Ballast-Deck Trestle positions in comparison to Dump Trestle location.

I don't really like this alignment of the trestle tangent with relation to where I can have the Deck Trestle.  I'm planning to move the west switches of Owenyo farther left, completely on Owenyo #2 Module.

The trestle spur with five "offspot" GS gondolas.

The other consideration in this pondering is how much extra length there is in the "Off-spot" portion of the spur, it's about 7 car lengths long. 

Another view of the trestle tangent and main track.

So one option is that I could cut the spur loose, and shorten the tangent along the right-wall, which would rotate the spur's alignment around the main track, pushing the trestle-wall contact point farther to the right, which I want.  It would also shorten the spur's tangent, keeping maybe only 5-6 car lengths of off-spot space.  

So.... Transfer Trestle Tangent Alignment?


This will be the view of anyone entering the room and seeing the layout for the first time.

One issue I also have with this current alignment is that the end of the Dump Trestle is pointed too much at the right wall.  It would be nice if I could have it rotated around to the right more, where I can see the southern (right) end of the trestle, more like some of the photos of the prototype.

Here's an overview of the whole module with 9 GS gondolas and an 18" radius curved backdrop mock-up.

One of the things I'm considering right now is the alignment of the trestle tangent against the rest of the layout.  I've consistently felt that it was forcing too much selective compression right at the joint between Owenyo #2 and #3 modules.  Even with the trestle hitting the backdrop and becoming a foreshortened image on the wall, the NG track behind the live stock transfer platform is really short. 

In Closing


This pretty well wraps up where the construction of the module is at this point.

In the next construction steps, I'll be working on cutting new strips of material to form the spline roadbed, make an adapter for the right end-plate for the spline, and also preparing to cut the spur roadbed and experiment with the rotational position of that spur.

Hopefully, I'll be able to get this module's frame work sorted and start working across the doorway. I'll probably need to have the main track built across the doorway with track layed and supported on the far end by the Bartlett module to actually be able to switch Owenyo.

Jason Hill


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