Project - How To Build the Waipahu Low Trestle Bridge

Photo 1 Copyright 2019 Nicholas Kalis
Trestle scratchbuilt by Nicholas Kalis

Utility poles scratchbuilt by Nicholas Kalis using toy beads.

Photo 2 Copyright 2019 Nicholas Kalis

Project

This Fn3 model is of a single-track straight low wooden trestle bridge spanning a gulch on the island of Oahu, Hawaii (appearing in a photograph of 1946 – see page 65 of

Sugar Trains Pictorial). The caption of the only photo I have found, locates this trestle bridge near the Waipahu sugar mill owned by the Oahu Sugar Company on the island of Oahu. The prototype was built sometime after 1897 when the Oahu Sugar Company was incorporated and before 1946 – the date of the only available photograph (Cochrane Collection). I have been unable to locate any plans for this trestle bridge.

 My entire trestle bridge was scratch-built of wood using a hot glue gun except for a resin steel barrel and Preiser pigeon 47084 1:25 scale and NBWs.

Tracks

 Both the prototype and this model are single-tracked. I hand spiked the rails using Llagas Creek Railways spikes.

Bents

First, I assembled – using hot glue - a jig of plywood and strip wood. I used a MicroLux® miniature table saw to cut my wood to size. I then assembled my multiple wooden bents using a hot glue gun and Surebonder Glue Sticks. Once cooled, I removed excess glue with my finger nail. I sought to match the height of my bents to what appeared in the Sugar Trains Pictorial photo. Following the prototype, each scratch built bent consists of four posts, a pair of sway braces, a sill and a cap, all of wood. Holes were drilled for Grant Line Products #3912 NBWs which were installed with white glue. All NBWs on my sway braces were painted and weathered.

Intermediary Sills

I followed the prototype bents seen in the Cochrane photo, as this trestle was low, and included no intermediary sills in my model.

 Girts

Following the prototype, my bents were stabilized by wooden girts (horizontal boards tying my bents together) which were hot glued in place. I drilled holes for installing my Grant Line Products #3912 HBWs with white glue. NBW were affixed even on the side of my model not visible from the aisle. All NBWs on the girts were painted and weathered.

Platform

My model’s platform was built of strip wood which were repeating “sandwiches” of three wooden stringers cut to what I believe to be prototype length. My model stringers are separated by spacers following prototype drawings of similar bridges. Grant Line Products #3912 NBWs were affixed with white glue.

Ties

 I used a WT-260 glue gun to glue bridge ties (a commercial product) to my modeled platform using care to assure they were evenly spaced.

Wooden Guard Rails

I then cut to length wooden guard rails on both sides of my Llagas Creek Railways steel rails. My wooden guard rails were attached to wooden ties with hot glue using a WT-260 glue gun. Wooden guard rails are outside the modeled rails. Holes were drilled for attaching Grant Line Products #3912 NBWs at the end of each wooden guard rail. NBWs were affixed with white glue.

Alignment

Care was taken to align my model trestle bridge with approach tracks and with the elevation of my two embankments.

Weathering

I also weathered all my wood with a black wash and with crème paint that was rubbed off quickly after applied. I even added a bit of mold using green craft paint.

Water Barrel Platform

Even though no such water barrel platform was visible in Cochrane’s photograph, following general prototype practice, I built a platform of strip wood to hold a water barrel for fire fighting. Holes were drilled for attaching Grant Line Products #3912 NBWs. NBWs were affixed with white glue.

Details

 

Mininatur O scale English Ivy 936-325 was glued to my model bents and sill to depict vines growing on this trestle bridge. Preiser pigeons 47084 1:25 scale were glued on my model. Using Envirotex two streams were modeled under my bridge trestle.

Commercial Components

·         Grant Line Products #3912 Hex Nut on Round Cast Iron Washer

·         Preiser pigeon 47084 1:25 scale

·         Manufacturer Unknown Turnout Wooden Ties

·         Mininatur O scale English Ivy 936-325

·         Llagas Creek Railways Spikes

·         Llagas Creek Railways Individual 6-foot rail sections Code 215

·         Manufacturer Unknown barrel

Materials Used

·         X-Acto® craft knife

·         Manufacturer Unknown Poplar 1/2" x 1/2"
·         Manufacturer Unknown Bass strip wood 3/16" x 3/8"
·         Surebonder Glue Sticks 4-inch x .43 in
·         FolkArt Acrylic Paint, Plaid Color 938 Licorice
·          Elmer’s white glue