JP Structures Cimarron bridge

D&RGW PIN-CONNECTED DECK TRUSS IN 1:48 O-SCALE. (On3, On30)
A nice deck truss will be my next model. The D&RGW had replaced an older wood deck span at the entrance to the Black Canyon near the town of
Cimarron in 1891. It is yet another recycled bridge from the D&RG mainline, as were the missing connecting girder spans. The span is a bit under
120' long.
There is another span just like this one. The "High Bridge" over the Animas River near Tacoma, CO is the twin transplant from the D&RG. It is still in
use on the old Silverton branch. However, it has suffered from a disfiguring but necessary strengthening to support the big Durango & Silverton
Narrow Gauge Railroad locomotives.

The model will be made from my thin
resin castings and etched brass. It
will of course include full-length steel
stringers so your heavy MMI locos won't
end up in the river. This bridge has lots
of rod braces that are very visible. They
will be reproduced per the prototype.
The bridge will require some type of
connecting spans. I will not be including
the end support frame (the part with the
sign) but I will provide brackets for
connecting plate girders right to the
bridge like this prototype had. The High
Bridge uses wooden trestles to connect
to solid ground, so the choice will be
yours.

I received a CD of bridge photos
courtesy of Glenn Farley including
the two reproduced here. I especially
like the one to the right with the sun
highlighting all the lacing bars and rivets.
Yummy stuff for a bridge fan. The model
will have the channel sides of the beam
cast in resin and the lacing and plates
made in etched brass. The combination
will make for a remarkable appearance
of scale thickness, rivet size and beam
proportion.

I AM RECEIVING MASTER PARTS FOR THE CASTINGS.

STEREOLITHOGRAPHY: I decided to use a rapid prototyping process to have master parts made for
the cast kit parts. Rather than making everything by hand, the SL process coverts a 3-D CAD drawing
into a solid parts with the look and feel of plastic. I get to design in contours, angles and features that
would be difficult or impossible to make by hand. It is an investment that yields more realistic parts in
far less time.

PARTS: The beam sides and floor beams will be resin cast. I will use etched brass for the beam
lacing and other details. These technologies are a good combination that will make this bridge better
than imported brass models, which tend to use thicker casting techniques for the beam lacing.

ASSEMBLY: I will provide fixtures for assembling the beams. There will be a lot of CA gluing for the
modeler but the fixtures should hold everything aligned as you glue.

GETTING ONE: I do not have a delivery date or price ready yet. I will update this page as I reach
milestones in the kit development. Remember, this is a very part-time endeavour.

MORE: Cimarron Bridge at DRGW.net has great info and photos of the bridge. Also, please feel free
to email corrections about anything about the bridges.

Thanks for your interest in my second cast resin bridge model. Email me for more info. Check back
for the latest news!

John Palecki

copyright 2005-2011 by John Palecki

These are photos of progress that I am quite excited about.
I decided to use stereolithography to make the masters for my
cast parts. I can get contours and variable wall thickness that I
could not make with hand-made styrene parts. Plus, I don't have
to emboss all those rivets myself.

The photo below is a rendering from my CAD for one of the
vertical beam sides. The photo at left shows the relative size of
four beam sides (one pair each for the end verticals and mid
verts). The photo at lower left is a close-up of the rivets from the
stereolithography process. I selected a high-resolution process
that lays down .002" thick layers of material. You can barely see
the thin layer lines in the rivet domes as well as the shape of the
domes from the CAD simulation of a spherical surface. They will
not be visible on the castings once a layer of paint is applied.