NOISY CREEK TRESTLE – 1— BASIC STRUCTURE

Closely following my model construction of the signature Salt Creek Trestle has been work on Noisy Creek Trestle.  Noisy Creek Trestle is the next major trestle up the Cascade Line from Salt Creek.  It crosses a steep ravine and is sandwiched between tunnels.  My model occupies one of the corner curves in my layout room, just as the prototype trestle is built on a curve. 

Noisy Creek Trestle posed new model construction challenges, mirroring issues the Southern Pacific faced with the prototype trestle.  Part of the prototype span fell down into the ravine in December 1964 due to a very heavy Pacific Coast storm.  A couple of freight cars are still down in the ravine, as well.  Another heavy storm in January 2008 led to a major mudslide nearby.  The damage from both of these storms closed the Cascade Lines for a couple of months each time.  While not facing storm effects, I did face construction challenges.

Views of the trestle can be seen on Joel Ashcroft’s website at:

http://spcascades.railfan.net/structuresNoisyCreekBridge.html

Noisy Creek Trestle is three hundred feet long and features three towers and seven girder spans.  Almost every tower leg is a different length.  I am glad I developed construction techniques for different leg lengths with the end towers for Salt Creek Trestle.  Noisy Creek required all of that knowledge.  Follow along with the picture captions the construction and initial installation of this second major trestle.

Noisy Creek Trestle girders in place on the aluminum strap spine.  The girder spacers are the black blocks crossing the spine to hold the two girders parallel to each other.

Noisy Creek Trestle tower bents.  Note that almost every leg is a different length.  Even the same-length legs of the left tower required shortening the legs and cross struts from the original Micro Engineering castings.  I built the bents for the left tower twice, trying to get the strut gusset plates in the right places.

Noisy Creek Towers assembled and painted aluminum.

Noisy Creek Trestle with girders, towers and track in place.  Most of the tower leg piers were scratch-built from styrene to fit their individual height needs.  The right tower rests on more substantial piers—a result of the reconstruction after the 1964 storm damage.  The towers rest on support plates that in turn are adjusted to the correct height by a diagonally-cut 2x4 with splice plate (facing).  Note the rock sheds at both ends of the trestle.  This is rugged terrain!

My tandem construction of two of the three major steel trestles on the Cascade Line proved time-efficient and definitely moved me along toward completing these signature structures.  The learning curve for building Micro Engineering trestle towers is such that my first one for Salt Creek took several days, but the towers for Noisy Creek each took only a bit more than a day apiece.  Further, I could apply all other construction lessons learned with the simpler (though longer) Salt Creek Trestle on the more challenging Noisy Creek Trestle. 

My final Cascade Line steel trestle, Shady Creek, will have to await another break in my formal operating session schedule.  Track alignment choices I made during primary layout construction prevented me from installing the trestle spine.  The new spine has been formed and awaits installation.

SALT CREEK TRESTLE – 3 – UNDERPINNINGS

Salt Creek Trestle has been a major focus for me over the holiday period.  Prior posts on the trestle can be seen at:

https://espeecascades.blogspot.com/2017/12/salt-creek-trestle-1.html

https://espeecascades.blogspot.com/2018/01/salt-creek-trestle-2towers.html

With the trestle girders in place on the spine and the towers built, it was time to install the trestle into the layout structure.  The critical part of this involved getting the towers to the right height above the scene plywood base plate such that they actually support the trestle girders. 

The first step involved making tower base plates upon which the tower piers and additional height supports were mounted.  As seen in the prior post and repeated below, the plates were roughly 4 x 5-inch pieces of plywood with the tower piers attached.

Salt Creek Trestle towers mounted on their base plates.

I created a master and mold and cast the piers in Ultracal30 ™.  The piers are truncated pyramids using the standard 12:1 batter for SP concrete bridge parts.  My November photo expedition confirmed this shape.

Salt Creek Trestle Tower Pier with travel companion and regular operator Jim M. standing alongside for size reference.  Jim is six feet tall.

Trestle Pier Mold Master.

The piers were mounted to the base plate and additional risers installed where needed to account for shorter leg lengths.  Those shorter leg lengths reflect the sloping terrain.  I will fill in around the piers and cover the risers with scenery material when I work on the scenery for the trestle.  A quick coat of paint representing a concrete color finished the tower plate preparation.

The tower base plates were mounted to pieces of 2 x 4. The 2 x 4 supports were cut close to the overall height needed for each tower mounting.  These were then cut into two pieces along a 45-degree angle to provide height adjustment.  I used 2 x 4 for this to provide lateral support as well as height.  A splice plate was attached to one post piece.  The post and tower assembly was fit into place and the final height secured, first with a C-clamp, second with screws.

Establishing the height for the 2 x 4 support posts to be mounted under the trestle towers.

Trestle tower height adjustment.  Note the up-hill tower legs have filler pads on top to provide for the mountain grade the track and trestle maintain.  I had to use C-clamps, which are relatively balanced, rather than the spring clamps seen to the right.  The spring clamps caused the assembly to tilt over to the side.

Salt Creek Trestle grade check using an electronic level.  The five tower heights were adjusted to maintain a steady grade.

The final piece of the underpinnings for the trestle involved the trestle abutments for the ends of the trestle.  These are cosmetic for my trestle.  I built them from styrene sheet and strip.  They are relatively simple shapes, not even having the usual bridge batter, as seen in my prototype pictures.

Trestle end abutment in place.  The abutment is supported by a block of 2 x 4 and held in place with adhesive caulk.

Mike L. controls a RR-Eastbound over the new Salt Creek Trestle during my January 2018 operating session.  Major railroad elements are coming together to form scenes of the Southern Pacific in the Cascades.

SALT CREEK TRESTLE –- 2 —TOWERS

Continuing construction of my model of Salt Creek Trestle, the next major element to add was the trestle towers.  The girders were covered in the first post of this series:

https://espeecascades.blogspot.com/2017/12/salt-creek-trestle-1.html

That post included a prototype photo shot from the RR-East end of the trestle.  Five towers were needed for this trestle, with the end towers having shorter legs near the ends of the trestle to account for the sloping ground. 

I needed additional photos to help with modeling.  Fortuitously, I had an opportunity to drive past Salt Creek Trestle on my way south to the Southern Pacific Historical and Technical Society Annual Convention in November.  That netted additional overall and detail photos just as I was building the trestle towers.

RR-Western-most four towers of Salt Creek Trestle.  November 2017.

A half dozen years ago, as I was planning the layout, I began stockpiling parts for my steel trestles.  I knew these trestles would be signature features on my railroad.  At that time, the best choice short of total scratch-building was to use the trestle towers from Micro Engineering (255-75169).  The middle three towers were relatively simple modifications to the Micro Engineering kits, trimming them from three panels high to two panels high. 

The two end towers needed further trimming of the end legs, closest to the ends of the trestle.  As shown in the photograph above, the RR-Western tower had a full upper panel and a half lower panel, with the end trestle-bent legs just one panel high.  This also was a simple modification to the Micro Engineering tower; just cut off all of the excess leg height.

RR-West trestle tower under construction.  The two bents have been trimmed to height and the first horizontal strut is joining the two bents.  Assembly on top of graph paper helped keep the assembly square with the addition of a measuring square to assist keeping the short bent square to the horizontal strut.

The RR-East trestle tower posed more of a challenge.  Indeed, with most of my photos shot from this end of the trestle, this tower had evaded much of my photography.  That fortunately timed trip in November provided an easy way to supplement my photos.  

The RR-East trestle tower for Salt Creek Trestle.  Amtrak Number 14, the northbound Coast Starlight, passed over the trestle while we were shooting detail photos.  This was a good day!  Note the end trestle-bent legs are shorter than the legs closer to the road (Oregon Highway 58).  The longer legs are the same length as the legs on the middle three trestle towers, seen in the top photo.

Shortening the uphill trestle-bent legs required both shortening the leg height and shortening the bottom horizontal bent-strut.  The initial assembly of a Micro Engineering trestle-bent starts with gluing two face pieces together.  I chose to make the cuts and re-splicing of the horizontal strut at opposite ends of these pieces so one side would have the originally molded part opposite the splice on the other face piece.  The rest of the assembly continued that philosophy, providing a strong final assembly.

Splicing the trestle-bent pieces together for the RR-East bent for the RR-East trestle tower of my model Salt Creek Trestle.  The pencil outline on the graph paper shows the original height of this bent.

Eventually, I had five assembled trestle towers with appropriate leg heights.  A coat of aluminum paint prepared them for use.

Trestle towers assembled for Salt Creek Trestle.  The trestle piers and under-pining will be discussed in a future post.

Salt Creek Trestle with girders and towers in place.

With the trestle girders and towers in place, my model of Salt Creek trestle was taking shape.  Future posts will cover the underpinnings and the walkways.