Harp Switch Stand

blender screen shot
blender screen shot

The Harp Switch Stand is the device used to “bend the iron” or move the rails on a stub switch. This post describes how I built a model harp switch stand for the Gilpin Gold Tram. Check out another post (not completed yet) that describes the stub switch itself and shows how the harp switch stand is integrated with the moving rails.

This is a part of my series on how to model the Gilpin Gold Tram which is a unique 2 foot gauge tramway built in Gilpin Colorado in the 1880’s.

*** this is a post in progress ***

I designed the model using Blender at 1:1 scale (i.e. full size). This way, you can export the STL files at different ratio’s and print the harp switch stand for different scales. There are several popular scales for modeling 2 foot gauge railroads which you can read about here. My preferred modeling scale is 7/8’s or 7/8 inch to the foot and so the images you see here are for that scale.

Design

HARP DRAWING
HARP DRAWING

The drawing above illustrates a typical harp switch stand from that era used by the Union Pacific (note the UP marking). This provides a general idea of the dimensions for the switch stand.

Gilpin Tramway Harp Switch Stand
Gilpin Tramway Harp Switch Stand

Here’s a closeup of the harp switch stand from the Ferrell book. I think I’ve captured the design fairly well but probably need more detail on the “pivot” hole in the center of the stand. There also appears to be lettering at the top but I can’t make out what it is.

blender screen shot
blender screen shot

Here’s what the 3d model looks like in Blender. The throw bar and linkage isn’t shown in this screenshot.

Lychee Slicer screenshot
Lychee Slicer screenshot

This is a screenshot from the Lychee slicer (I use the free version). It’s angled at 45 degrees with automatically generated supports.

3D Print

Harp switch stand on supports
Harp switch stand on supports

Here it is fresh off the printer. I use a Mono 4k resin printer. For a first try this came out pretty good.

harp switch stand
harp switch stand

Now we see it off the sprue and ready to finish!

And Finally…

If you want to see how this is installed on the stub switch check out this post. If you are interested in the STL file hit me up on LinkedIn or leave a comment below. I also post on the SE Lounge which is a great forum for light industrial railways.

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