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Saturday, July 28, 2018

EAGLE CREEK BRIDGE

The canyon spanned by Shady Creek Trestle needed a water outlet for the implied drainage.  That water course needed to cross under the lower mainline--the line between McCredie Springs and Wicopee.  Studying the bridges along the prototype Cascade Line, my attention was drawn to the short span over Eagle Creek.  http://spcascades.railfan.net/ICCEagleCreek.html   Photos in the McCredie Springs to Heather section: http://spcascades.railfan.net/structuresMcCredie-Heather.html  This short (40 feet long) through plate girder was just what I needed for my scenery. My lower level track has relatively flat scenery after the deep gorge of the canyon above it, spanned by Shady Creek Trestle.  I just needed something "plausible."

Once again, I turned to the Central Valley 72-feet through plate girder kit (210-1903) that I have used for so many bridge girders on my railroad. For once, I was going to use it as an actual through plate girder bridge!  I still needed to cut it down to my desired length and match the girder end treatment of the prototype span.  This was accomplished easily, as Central Valley uses a relatively soft plastic for molding their kit parts.  That is one of the reasons I have used so many of these girders around my railroad.

With the basic bridge built, I could turn to cutting the required gap in the track roadbed.  Identifying a structural panel that I wanted to install the bridge within, I spanned the panel with a plywood base.  I then cut abutment blocks that I glued between the roadbed and the base plate. This provided additional roadbed support that will keep the roadbed in vertical alignment.


Plywood base installed for the future Eagle Creek and bridge.


Roadbed abutment blocks installed.  Two sets of cut lines are drawn on the roadbed.  I shifted the bridge to the left set.

I then removed the flex track segment that spanned the bridge area.  This allowed me to use my finish router to rout a channel into the roadbed.  This channel was cut to the depth needed to support the cosmetic bridge abutments and the bridge.  I then cut the roadbed gap with my circular saw.  In the end, I got a bit too vigorous with the saw--I cut the gap too wide.  I fixed this by gluing end plates composed of my 1/4-inch hardboard spline material cross-wise against the edges of the abutment shelves.  


Eagle Creek roadbed gap cut.  I have begun filling the creek-bed in with styrofoam.

With the gap cut and appropriate abutment shelves built up, I installed the cosmetic abutments.  I needed to shim the abutments to get the bridge to the right height relative to the roadbed.  Micro Engineering bridge track has thicker ties (0.100-inch) than their regular flex track (0.080-inch), so this needed to be accounted for when checking height with a steel straight edge across the span.  I let the caulk used to install the abutments set up and then began filling in the rest of the terrain around the bridge and creek.


Eagle Creek bridge test installation while the caulk sets holding the cosmetic abutments in place.  

I made quick work of the foam base carving and shaping.  While I was at it, I added styrofoam panels between the roadbed and the fascia throughout the immediate area.  After the caulk used to attach the foam set, I went back with my saber saw to cut a new terrain contour along the fascia.  Finally, I mixed up a large bowl of Sculptamold with paint mixed in and applied it to the pink foam.  I try not to leave "raw" pink foam on my railroad for very long. I find it distracting.

The track was re-installed, now with a bridge track segment.  Feeder wires were attached and the railroad was returned to service.  This is the last of the mainline bridges on my railroad.  I still have a branch-spur track bridge set to go, but the mainline has all of its bridges now!


SP X7480, an EURVY (Eugene to Roseville mixed freight) crosses the new Eagle Creek bridge.


A wider view of the SP X-7480 crossing Eagle Creek showing the now released "drainage" from the Shady Creek canyon above it.  The tunnels on the upper line on either side of the trestle will be closed in after my August operating session.  The track-work on the trestle and within the tunnels needs to have train test runs over it by operators other than myself before I close in that track.

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