BRIDGING THE GAP: WILLAMETTE RIVER BRIDGES – 1

An overdue project entails closing the track gap between Springfield and Eugene.  Although the primary structures, a pair of Walthers single track through truss bridges (933-3185), have long been built, I needed to build most other parts of the scene. 

Bridge piers were high on the list.  The prototype piers are fairly simple concrete shapes.  The standard SP 12:1 batter (downward slope) and 45-degree cutwater ends can be seen in the prototype photo taken last Spring.

Willamette River Bridge from Springfield, April 2013. 

I considered various ways of replicating these piers.  No commercial castings satisfied the need.  I settled on cutting them out of wood blocks using my table saw and compound miter saw.  After a trial run using a fir 2x4, I settled on using poplar as the wood.  This is a close-grained wood readily available in local home centers.  A six-feet long 1x4 plank became three pieces laminated to provide a 2-feet long 2.25 inch thick block.  The overall height and long dimension batter was cut with the table saw.  A 12:1 batter works out to about 5 degrees angle, easily set on both saws.  The compound miter saw was set for the 5 degree batter and 45 degree cutwater ends (using both saw angles available).  Lots of careful setup and clamping were necessary!

Progressive formation of bridge piers.  Fir 2x4 trial pieces are on the left.  Laminated poplar block with 12:1 batter from table saw is next.  Completed bridge pier is on the right.

The poplar piers were filled and sanded.  Multiple coats of “rattle can” Rustoleum gray primer were used to seal the wood and provide a base color coat.  I am undecided as to whether I will use this base color or go with a bit lighter gray shade provided by hobby paint “concrete” colors.  The prototype photo shows lots of dark gray splotches, typical of weathered concrete here in Western Oregon.

Moving on to the Eugene side approach, I am using a single Micro Engineering 50-feet deck girder span.  The prototype bridge uses a steel trestle affair, but I needed to compromise to a single girder span given the available space.  Note those same space considerations led to the use of the Walthers through truss bridges rather than one pin-connected truss (similar to the Central Valley truss, 21—1902) and much longer curved chord truss of the Eugene span. 

A “concrete” bridge abutment was built using styrene.  I am very familiar with fabricating styrene parts so this seemed the best way to capture the desired shape.  The resulting abutment features a pocket at the top for the girder to rest within.  This gives way to the standard SP 12:1 batter sloping down.  I’ll add wing walls later as the scene develops.  The abutment is fabricated for mounting to the underside of the plywood subroadbed.  All of the bridge parts will remain removable until the river scenery is formed and the river painted. 

Front of Eugene bridge abutment.

Underside of Eugene bridge abutment.

In addition to painting the concrete parts, I also needed to paint the steel bridges.  I ultimately had to unpack my airbrush and hook up the compressor.  These highly useful modeling tools have languished in packing from moving FAR too long!  With the abutment fabricated and mounted and the piers placed, the Willamette River bridge structures are coming together.

Willamette River Bridges in process.

I’ve chosen to mount the bridge track directly to the “steel” bridges, making them “open deck.”  The prototype through trusses are open, but the approach spans are ballasted decks.  The Micro Engineering deck girder matches the height of the Walthers through trusses.  There is not enough clearance on the through trusses to add a ballasted deck, so I chose to keep both them and the approach span open. 

Bridge track is one of the next steps.  I am using Micro Engineering bridge track.  I began by painting the track an overall gray-brown.  Historically, my first choice would have been to use a “rattle” spray can of Floquil Rail Tie Brown.  Unfortunately, Rutstoleum-Testors discontinuance of the Floquil paint line this year eliminated that option.  Instead, I used a combination of a pair of Rustoleum (ironically!) spray cans: Espresso and gray primer.  I sprayed the brown first and quickly followed with a light misting of the dark gray primer.  The mottled effect provides a good base for further paint detail.  Detail was supplied using Floquil paint pens (which I could still obtain), using roof brown and weathered black on several ties.  A Woodland Scenics “steel” paint pen was used on the side of the rails.  The overall effect looks quite good to my eyes.

Painted and “weathered” bridge track.

Still to come is the pile trestle approach on the Springfield side as seen in the prototype photo above.  Having fabricated the bents from styrene, I discovered I had not obtained the right size of strip for the trestle stringers.  An urgent trek into Portland for the larger hobby shops there provided the necessary materials.  I hope to report on completion of the track over the river next time.