Monday, July 30, 2012


Actual building of the HO scale SP Cascade Line has begun!  The first step was cutting up plywood into “dimensional” strips for use as L-girder and stringers for the base level of the railroad. 

Plywood is being used for dimensional stability.  Too many folk (local and nationally) have reported problems with solid lumber warping, often well after initial construction.  The alternative of kiln-dried lumber is both expensive and can be unsatisfactory as well.  The initial delivery of K-D lumber to be used for legs was rejected as it had far too many defects (knots and edge of trunk cuts) to serve my intended use.  I hand-selected the replacements.  The lumber industry has changed a great deal from when I was growing up here in timber country—Oregon.  Plywood largely overcomes the warping issue of solid lumber, albeit at the expense of alternative edge joining techniques.  Screws don’t hold as well in the edges of plywood compared to solid lumber.

Plywood loaded into truck prior to becoming “dimensional lumber.”  Underneath the ply are rejected 2x6 intended for legs.

Eleven sheets of seven-ply A-C plywood were cut into “dimensional lumber.”  Most were cut to 3-7/8 inches wide to serve as L-girder webs (vertical piece) and stringers.  Two sheets were cut into 1-7/8 inch strips to serve as the L-girder flange (top cap).  This should be enough to support the base level of the railroad.

July 30, 2012 became a red-letter day.  The first L-girder was assembled!  Construction truly has begun!  The first L-girder will be attached to the central post, on the Eugene side.  It is composed of four 8 feet lengths of 3-7/8 inch wide web and 1-7/8 inch top cap with offset joints.  Glue and screws were used to attach the top cap to the web.  The coarse thread wood screws should be sufficient to hold the top cap in place as the glue sets.

First L-girder resting on stringers. 

L-girder detail

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