Saturday, February 3, 2018

SALT CREEK TRESTLE – 4 – WALKWAYS AND HANDRAILS

The final major element of my Salt Creek Trestle model consisted of adding walkways and handrails.  As noted in my earlier posts on this project, I chose to model the trestle in its post-1962 appearance with aluminum paint.  About the time of the repaint, SP shifted to using steel grid walkways and cable handrails.  Modeling both of those features presented new challenges compared to my earlier bridge work with mostly ballasted-deck bridges and wood handrails.  New modeling approaches were needed.

The prior posts on my Salt Creek Trestle model can be found at:




Several of my detail photos from my November photo expedition provided important modeling clues for this effort.  I shot photos from the highway looking up.  This revealed the walkway support structure and another detail I had not noted previously—a debris shield over the highway.


Salt Creek Trestle underside detail.  Note the Apex-style (rectangular slot) walkway, the trestle crossbeam walkway supports, and the cable handrails.  The walkway support crossbeams pass under the rails forming a continuous beam from side to side.  Also note on the right side of the photo the solid debris shield which covers the span over Highway 58. 

In the photo, I noted walkway crossbeams were spaced three ties apart.  I modeled the crossbeams with Evergreen styrene 0.040 x 0.100-inch strip.  This has the right cross-section and fits the height of the bridge ties on the Micro Engineering bridge track I used.  Note further that every other crossbeam has a handrail post. 

I chose to use “wood” posts rather than simulate the steel posts on the prototype bridge.  This was a practical matter of choosing function (holding the cable handrail) over form (thin steel posts).  I used Evergreen styrene 0.030 x 0.060-inch strip for the posts.  This provided adequate post strength when I drilled holes into the post to pass the handrail wire through.  Further, I could glue the posts to the crossbeams using standard styrene cement and expect it to hold.  Finally, I found I needed to repair a few posts as I worked with the handrails.  Such repairs were easily accomplished using a fast-acting styrene cement. 

I cut the crossbeams to HO-scale 17-feet pieces.  After drilling a pair of handrail holes in the posts, I glued them to half of the crossbeams.  I chose to use only two “cables” for my handrails rather than the prototype three.  Perhaps I was being lazy, but more importantly, I did not want to weaken the post still further with yet another hole.  The post assemblies and separate strip material for the other half of the crossbeams were painted a “tie brown” color using a Rustoleum “Camouflage” rattle can. 

I prepared the track by filing through the tie-web every third tie.  The tie-webs were the thin strip of tie material that connects the tie strip on alternative sides under Micro Engineering track.   I then worked on the underside of the track, installing crossbeams using canopy cement.  The canopy cement assured a good bond, even with the slippery plastic used for the tie strip.


Crossbeam installation on underside of track.

I modeled the highway debris shield with strips cut from Evergreen 0.010-inch thick styrene sheet.  I cut these pieces four HO-scale feet wide and then cut them into segments to account for the curve my trestle track uses.  The shield plates were painted prior to installation with the same “tie brown” color.  Attachment to the crossbeams was with canopy glue.  Evergreen styrene 0.020 x 0.120-inch strip formed the vertical shield on the outside of the walkways.


Model debris shield.

The walkway grid was cut from Plano #201 stainless steel Apex grid scratch-builder material.  I cut this material into nominal 3.5 HO-scale-feet strips to fit between the ties and the handrail posts.  A shout-out to Plano http://www.planomodelproducts.com/ is appropriate here.  They have an amazing array of etchings for model railroaders, mostly for diesel locomotive detailing, but also for various designs of freight car running boards.  From that, they also found a market for the scratch-builder material using running board patterns in both stainless steel and brass.  My order took less than a week to ship (that day!) and arrive via USPS priority mail (normal shipping).


Salt Creek Trestle Model with Apex grid walkways.  Barely visible (no contrast with the ties) are the outside guard timbers outside of the rails, but inside of the walkways.  This photo has my second attempt at cable railings using strands of copper wire.

The final detail for the track and walkway structure was the cable handrails.  I chose to model my trestle with only two of the three cables, as each hole in the support posts would weaken them.  This proved correct, as I broke several posts at the lower hole during the cable threading operation.

It took three separate attempts for me to find an acceptable solution for the cable detail.  My first plan was to thread stainless steel 0.010-inch diameter wire through the holes.  Unfortunately, the supply of Detail Associates wire has dried up, so I needed to substitute phosphor bronze wire from Tichy, at least for the lower cable.  I had enough of the Detail Associates stainless steel wire for the top cables.  I abandoned this attempt after threading one lower cable with the bronze Tichy wire.  The shorter segments of wire from Tichy (about 7 inches versus 12 inches for the Detail Associates wire) meant many more joints between wire segments.  Further, though I could color the Tichy wire with an aluminum/silver Sharpie, this was a tedious and incomplete process.

My second attempt at modeling the cable handrails involved using strands of copper wire from a stranded wire speaker cable.  I split that cable into its two parts (manufactured as joined, paired wire such as in common extension cords).  I then stripped one of those wires.  The one I stripped was plated silver, so the color was right to begin with.  This nicked or broke a number of the strands over the more than six-foot length I worked with, but that still left a large number of intact strands. I then laboriously unwound individual strands.  This wire was even finer than the Detail Associates or Tichy wire at 0.007 inches.  I made an attempt to bulk this up a bit by twisting two strands together, but this proved very difficult to thread through the post holes, so I reverted to single strands.  Although this produced continuous cables over the entire length of the trestle (500 HO scale feet long), the copper wire proved much too soft.  I could pull it taught, but that would deform the track and posts.  This left unacceptable bends in the cables in many spots along the trestle.  This can be seen in the photo above of the model debris shield.

My third attempt at the cables involved using 0.015-inch steel music wire.  This cured the strength and straightness issue as well as providing the appropriate color.  With three-foot pieces of wire, only one joint was needed for most of the cables.  The outer cables required an additional short segment for the outer cables on the curved trestle deck.  I chose to place the necessary joints between segments near opposite ends of the trestle.  The result with the music wire cables captures the look I sought.


Final version of the cable handrails using music wire.  I sprayed flat finish on the completed structure which toned down the reflections from the walkway grid and handrail.  Electrical feeders are placed close to the rails at both ends of the trestle.  Look closely.  A coat of paint camouflages these wires.


The first train over the completed Salt Creek Trestle.  Rodger C. guides the BRLAT led by SP 9232 over the trestle.



Another view of the BRLAT crossing Salt Creek Trestle.  My vision for a model of the Southern Pacific in the Cascades is becoming real!

3 comments:

  1. Bill,

    Simply amazing! Kudos to you for the trial and error attempts at finding the right wire for the project. The finished railing really look great! It's one of those details that would have been obviously missing had you not gone to all of this effort. And the debris guard over the road is a nice touch. Well done!

    Tom

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  2. You modeling truly gives the feel of the Southern Pacific line over the Cascades. Well done. Keep up the great work.

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