Wednesday, September 22, 2021

SPMW 7021A (Part 3) Wrecker - Rail & Tie Car

I decided to do another few steps on the since SPMW 7021A (Part 2).  It's time to dive into the more delicate details of the rack.  

Installing Stringers

Since the last time I cut and installed 0.040"x0.060" styrene strips to fit between the vertical posts.  Specifically I wanted these to be wedged slightly longer thank nominal space so that the rack will put these stringers in compression to keep the rack from sagging.  Later I actually decided to insert a 0.010"x0.040" strip in between the frame rail and the A-end end sheet to force the floor to have a slight crown in it.

0.040"x0.060" Styrene strips cut and fitted between vertical H-posts.

Supporting the upper rack with a section of 1/4x1/8" styrene, I started drilling the marked center points for the grab irons with a No.78 drill bit.

Center stringers wedged in place.

Side grabs bent using the longer grab jig on the OwlMtModels F-50-series sprue, which is about 0.250" long.

Cutting Running Board Supports

NWSL Chopper used to cut up supports for running boards.

The Northwest Shortline "Chopper" is used to cut exact length pieces of 0.020"x0.040" styrene strip for the support frames.

Vertical and horizontal running board supports. (Vert supports above, Horiz. below)

I decided to fabricate the running board supports from four 0.020"x0.040" styrene strips, this allows a lapped joint at the corner.  The running board support needs to be 0.215" higher than the rack frame, and 0.315" wide for the horizontal support.  The alternate piece is cut 0.040" shorter, allowing for the lapped corner joint.
Pile of cut materials for running board supports.

Installing the Running Board Supports

Running board supports installing against gusset plate.

The first several supports I glued up and kept square against a metal square.  Once dried I installed them to the gusset (A-end) of the car.  

Running board support being installed - Right side

Running board supports being installed - Left side

3/4 end high view of running board supports and stringers

Later I went to installing the vertical pieces with Tamiya liquid glue, and then installing the horizontal pieces after the vertical had dried.

All running board supports installed.

Completed running board supports.

B-end close-up of running boards installed.

Structure of the rack coming together.  A piece of 0.009" PB wire will be strung through the top of the vertical rack.

Rack Bulkheads & Tie Fitting

2x6 rack end boards installed and ties piled in rack.

The next step is to fabricate the bulkheads in the end of the tie rack.  These were made from seven 0.020"x0.060" styrene strips with 0.015"x0.040" strips vertical on the exterior of the panel, glued together with Tamiya liquid glue.

A-end close-up with end boards and ties in rack

Installing the grab irons, the end grabs are using the standard F-50-series short grab jig.  The top corner of the A-end of the rack will have corner grabs on top of the running boards, like a boxcar have.

B-end close-up with end boards and ties in rack

The inside of the rack a longitudinal stringer on the inboard side of the H-columns is fabricated from 0.015"x0.040" styrene strip.  I may decide to fabricate a very small stringer to go between the flanges of the H-columns about halfway between the running boards and the top cable.

In Closing

SPMW 7021A at Bakersfield, post-1958 gray.  D.F.Willoughby collection

I'm saving installing the vertical structures hanging off the rack frame which the intermediate side grabs were hung from.  They will be pretty fragile, so I'll add them right before painting.  Most of the stake pockets had short stakes to help contain the rails and switch frogs, so those will be fabricated at some point soon once I get the rail & frog load built.

Finishing up this car should be pretty fun as this project is entering the home stretch.

1 comment:

  1. Beautiful work...I don't know how you stay sane since if I tried to do a project like this I would have slid off the deep end somewhere around having to cut and place all of those short supports.


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