NightOwl's Jawbone Branch: SP Jawbone Branch (Part 51) - Cutting and Aligning the Trestle Spur

In the last post, (SP Jawbone Branch (Part 50) - Fans, Surform Tool, & House Keeping) I was mostly doing a bit of house keeping and setting up the shop with a few minor improvements on the fans to work in the summer time. Thankfully, it's not yet surface-of-the-sun levels of heat, which will come in August and September.

So here's the starting point for the next round of work on the Owenyo #3 Module. I'm getting behind in posting these... I actually already have construction up to Part 52, but here's the huge pile of photos and thoughts from the steps leading up to where I'm at now!

I'm looking at changing the alignment of the trestle spur, plus shortening the "west" end of the module.

In these pictures I'm really looking at the alignment of the trestle spur. Not liking what I'm seeing with the alignment of the trestle and the room... It's time to start cutting!

Bye Bye Spur?!

Well, yes and no. I used the saber-saw at this point to section the top skin so that I can work with each piece in relation to the trestle and the room.

The top sheet for the Spur is cut off and allows me to play with the alignment.

As I mentioned in the last post, I want to be able to see the south or "west" end of the trestle more and not have it pointed as much at the wall. I'm pulling the spur roadbed around in relationship to the main line curve.

Playing with the location of the trestle, curve and how many cars will fit.

At this point I've cut the spur loose and shortened the top skin to be the same length as the shortened frame that I modified last time. In this alignment, I'm working out enough space on the spur for 4 GS gondolas under the dumping section of the trestle, and enough space for 4 GS gondolas to be off-spotted between the non-dumping end section of the trestle and the fouling point of the spur and main track.

This would work out as the shortened 4-car trestle position.

It's about this point that I start to get greedy with the layout design... Can I squeeze in another GS gondola to get the prototypical 5-car loading, and still have the approach ramp look half-way decent?

Now that the spur is cut loose, I can change position and alignment of the curve.

After a little more re-arranging of the spur roadbed, I've got 4-5 cars under the trestle, and four offspots, which I think is now a little short for the off-spots for the prototype, but I'm leaning towards having the full 5 spots under the trestle, so I don't have to do any selective compression to it.

As can be seen in the foreground, I've also roughed out a piece of Code 55 flex track for 48" radius main line curve, but as I'll be upgrading the main track to Code 70, this piece of flex track will be used over on the Little Lake Siding, as I want to keep the minimum curves there to 48" radius.

SPNG 9 on Owenyo Transfer Trestle - owensvalleyhistory,com slim rails20_sml

The issue with compressing the trestle is that on my layout, most of the viewing, as trains come into Owenyo or out, or are switching, will present a near dead-on side view of the trestle to them, which will show the compression.

Owenyo Dump Trestle from SW corner and SG side. - Richard C Datin Jr photo

I think the alignments I can get the trestle to now, should be able to show the same angle as the Datin photo above. The closer bent leg is aligned between the 2nd and 3rd set of rear bent legs. When I put my eye down near the track and the end of the Owenyo #3 Module, where the side of the narrow door spanning module will be, I can get about the same angle, which will be a good point to shoot for as a first impression as anyone enters the room.

My rough code 55 flex track trestle track is a little short for this exact combination.

The problem of course, is that the trestle should be about 7.5 feet long in HO, and it will hit the wall, so the only question is how much of the transition ramp section (prototypically about 250 feet) can I model before it has to become an image on the backdrop... or maybe, I could "bend" it to become a compressed flat along the wall, but also in a perspective compressed form, as I can't have more than about 12-15" of ramp along the backdrop before it starts hitting the stock transfer platform. - Maybe... I'll have to play with how I could make a slightly 3d flattened perspective version of the ramp parts...

More Pictures of the Trestle & GS Gondolas

Full spur with 8 GS Gondolas, the outer 4 being off-spotted.

I'm mostly coming to terms with the trestle only being 4 cars long, and the the off-spot space matching at 4 cars, which I think will make work for my operation plans. The foreground spur roadbed is actually climbing too steep, as I have it layed on top of the 1/4" main track roadbed sheet.

Zoomed in low-angle photo of the NG loading trestle.

I may still decide to raise the trestle spur a bit more. I believe the natural ground level should be about the height of the car's floor, or about 48" above the railheads of the spur.

High angle view of the trestle spur position.

Here's the space at the end of the spur looks like. I might be able to fit in another GS gondola, but that will really squeeze the transition and grade sections of the trestle against the wall.

Not really accurate position for the trestle, but if it was one more bent to the left.

This sorta shows the amount of space I have at the end of the trestle, where it transitions to the ramp sections.

New "Door Bracket"

Additional Bracket above the light switch next to the door.

The cantilevered west end of the Owenyo #3 module is a bit of a problem, as that it wants to twist without any support. I decided to put together a temporary bracket to support the end beam of the module. The main problem with this bracket being kept is the arm is too long, because I used one of the extra full-length bracket arms from the rest of the Owenyo-Mojave support brackets. The other issue is that the screws on this small plate don't actually catch a main frame in the wall. So I'll be looking to replace this support after I get the structure of the module finished up.

Roughing Front Curve Frame

The west end of Owenyo #3 Module

In these photos, I'm roughing out the front fascia strip. The main challenge right now is cutting more strips of material to make the main track spline.

This shot shows the permanent wall bracket just past the window, with the front fascia frame strip in place.

The vertical position of the curved front strip falls across the "window bracket". I roughed out the offset from the main track centerline is set for about 5", which is not maintaining a constant from the track. This should allow a little more foreground when I'm taking photos of the layout later, but it will also keep the layout across the doorway to a minimum width.

Clamping the weakened front frame joint

Sadly because I've not put in the rest of the cross bracing to support the front frame and keeping it's spacing correct and square yet, the front left corner joint cracked, so in these shots I'm re-gluing the joint, and holding it square against the spline roadbed base that I built during the last post.

A closer view of the wedge shaped curve joint between the front frame and the curved fascia frame.

The front fascia frame will be clamped for the first 2-2.5" past the joint and then I'll fill the wedge-shaped joint with glue in the future, but it's a good thing to check at this point in the build.

Track Supports & Grade Checking

I ran the grade calculations for a 1.25% grade, which is 1.25" rise in 100" run, 0.625" in 50", or 0.375" in 25". Unfortunately, my bubble level is only 28" long, which will mean I need a 0.0375" riser block. The only scraps I have handy right now are some 1/4" scraps. So that means I need to divide the 25" run into 2/3s, or 16.66". This length is about right to nicely slide along the top-skin roadbed and check the grade.

Temporary track support where the main track roadbed crosses the front frame member.

One problem is that the front frame piece is sagging just slightly. So I'll probably not be setting the grade without getting some more structure under there to support it first. I'll have to work this out before I finalize exactly how deep the notch will be made for the main track spline to fit over the front frame beam.

This shot shows the permanent wall bracket just past the window, with the front fascia frame strip in place.

For now I'm using a scrap piece of 1/2" MDF strip for the main track riser at the window bracket. This will be mostly replaced with the under roadbed spline, but I'll probably add a rib here to support the rear and forward curved fascia frames to keep the module square and stable.

Cheating to Part 52...

Showing underside of bubble level with 1/4" shim.

These are just a few shots from Part 52 timeframe, showing how I am using my bubble-level with 1/4" shim block 16.66" down the length, which works out to 1.25% grade. I cheated and made a few pencil and Sharpie marks to easily be able to align the shim with the level.

Mid-curve grade check.

The risers seem about right, matching the CAD model in my computer. All of this is rather guestimates, because the 1/4" MDF roadbed top skin is pretty flexible. Even the weight of the bubble level sitting between risers will change the grade and level readings.