Modeling G31 Series (G31, G31a through
G31m?) and G35 Gondolas
by Elden Gatwood
The 2900 G31 gondolas (with no suffix)
were originally built in Altoona during 1948 through 1951. The
G31s were welded, steel-floored, drop-end gons of 52'6" inside
length. Additional subclasses spun off from the G31 subclass,
identified as G31a through G31e, were also 52'6" inside length
mill gondolas, but had wood floors (identifiable by the small
"w" in a circle to the left of the keystone). The G31
series was a substantial class on the PRR. Later added sub-classes
G31f through G31m were rebuilds of the above classes G31 through
G31e. They were all originally 70 ton cars (140000 CAPY, about
155000 LDLMT, and about 55000 CAPY). The G35s were the same externally
as the welded drop-end G31a's and b's, but had a different underframe,
which won't make any difference if you don't model the underframe!
You should have a bunch of these for good representation of your
layout. If you aim to have 200 PRR freight cars, up to a dozen
should be G31 series cars. The easiest modeling approach, although
it still takes a lot of work, is kitbashing the ConCor/Revell
54' Mill Gon. They can be had for $4 to $6 each (less at swap
meets), another $2 for the Detail Associates ends for the fixed
end G31d or G31e, or mated-in ends from the Proto 2000 Greenville
Mill Gon for the G31 through G31c, probably another $1 for ladders,
$1 for Kadees, $1 for weights, and whatever for your choice of
trucks. So, you can do a really nice G31 gon for about $10.
Here's how it's done
- Remove all parts, underframe, weights, trucks, etc. The body
is all you'll use. Remove all paint. The best method is to dump
it in a bucket of Pine-Sol (or other mild paint remover) and take
it out after an hour or so to toothbrush off the paint. Once the
lettering is off, you can hose it off, let it dry, and shoot a
coat of paint on it. Use gloves with the paint remover! Don't
use your wife's toothbrush, or you will pay.
- For all but the G31c and G31e, all rivets should be shaved/sanded
off. Use a square-tipped blade to get most of it, then follow
up with 400 grit wrapped around a small block of styrene. Cut
off the stirrup steps, and shave off the brake retainer line (but
not the retainer, unless you have a good replacement) on the side
- The fishbelly sill needs to be shallower than that on the
Con-Cor model, so scribe a line 0.14" (12") up from
the bottom of the side and make progressively deeper cuts until
the entire lower side sill can be cracked off. Make a mark directly
under the 4th and 10th ribs and connect this to the point that
used to mark where the side sill began to go down (2nd and 12th
ribs), then scribe new lines downward (so a slip doesn't
ruin the body) toward the earlier mark, deepen them, then break
off these small triangular pieces. This recreates the shallower
transition to the bottom of the new sill. Smooth the cut surfaces
with a file, then sandpaper. Nice!
- Cut out the drop end (it has no detail on the inside, so we
will replace it) and file/sand down the remains flush with the
inside. File down the bottoms of the ends until these, too, are
flush with the bottom of the floor. Shave off the ladders and
grabs and sand smooth.
- (All except G31c) Using your sanding block, sand down the
sides of the 3rd and 11th ribs on each side until they are about
equal in width to the ones on either side. There should be 3 thin
ones in a row on either end (2 through 4, and 10 through 12).
You will probably have to use a knife near the top chord. The
G31c has alternating thin and thick ribs like the model, so you
don't have to do this step. Unfortunately, for the G31c and G31e,
you must now replace the rivets that you removed with the lower
side sill. Some like to shave rivets off of other models like
the Athearn 40' Box, but I leave this to you. Each rivet would
then have to be reapplied individually. Yuk. Better yet, model
a welded one.
- Using a file, take 1/8" off the top (actually, bottom)
of the truck mounting pins. This will lower the car to the right
- Assemble your Kadees in the boxes. Once dry, shave the lip
off the top of the box. On the "A" end (the one furthest
from the brake retainer), glue the box along centerline directly
to the floor and flush with the end. On the "B" end,
glue it along the centerline, but sticking out about 1/8".
- Create new end sills from styrene strip to match the distance
between the bottom of the floor and the bottom of the side sill.
The "A" end sill is flush with the ends. Two strips
that fill the gap between the coupler box sides and the inside
edge of the side sills will do the trick, flush with the ends.
The "B" end sill flares out to meet the coupler box
end. Cut two pieces a little longer than those for the "A"
end, and angle the ends until it looks something like an elongated
parallelogram and adequately fills the gaps on each side of the
- Create a new center sill from styrene strip. One piece goes
between the coupler box and truck mounting pin, the other goes
from the truck mounting pin to about even with the 3rd rib in
from the end. This leaves lots of room in the center for weights.
Don't install the weights until all detail and trucks are mounted,
otherwise the model will keep tipping right-side-up while you're
- Fashion a three-rung ladder from wire and brass strip, or
cut a commercial ladder down to length. Create "stand-offs"
from .02" x .02" strip, then mount ladders on the right
end of the sides. Drill and mount a single straight grab on the
left end of each side about halfway between the top and bottom.
Drill and mount straight grabs at the top of each side at the
ends, with one leg on the last rib. Drill and mount straight grabs
on either side of the coupler in the new end sills about halfway
between the coupler box and corner.
- For the drop end versions, either narrow a leftover Life-Like
Proto 2000 Greenville gondola drop end, or create your own from
DA ends or other sources to fit between the end ribs, slightly
inset from the end. The "early" Dreadnaught drop end
from P2K is appropriate for the G31a, while the other is more
appropriate for the other drop end models. The fixed end versions
need to have the end ribs on the side shaved off and replaced
with styrene strip narrower than the other ribs, set in slightly
from the end. Make 4 and taper the ends (bottoms). Cut down the
Detail Associates end and mount flush on the end. You will have
to do a lot of filing to get it to fit.
- On the drop end versions, glue a short length of chain under
the handbrake. Take a small piece of roofwalk material, angle
(cut) the back end so it looks parallel to the end, and mount
as a brake platform on the pointed "B" end. I use two
pieces of wire drilled into the end to support the platform. On
the fixed end version, mount a new brakewheel assembly on the
left side of the "B" end, and do the same for a brake
platform. Leftover LifeLike parts are great for this, but any
others will do. Most assemblies look like Ajax to me, but with
repairs, anything would be possible.
- Glue a length of styrene strip centered on the side of the
top chord, with just enough room on either end for the top grabs
you installed earlier.
- Drill and mount a new brake retainer line from .012"
- Drill and mount new stirrup steps. The hefty wire ones from
A-Line are good.
- Mount your trucks. They are NOT 2D-F8s with the droop under
the spring platform, but look closer to an A-3 or "Bettendorf"
style with the gradual taper to the bottom.
- If you choose to mutilate the model, do it now. A way to simulate
damage found on gons is to heat the end of an old hobby knife
and then press it against the inside of the side panels until
you have a dent in the outside between the ribs. It works OK.
- Clean the model. Paint with your favorite version of "PRR
freight car color". As-built (1950's) "freight car color"
is redder. Repaints are browner. A 50/50 mix of Floquil Zinc Oxide
and Box Car Red looks good for the original paint (Circle or Ball
Keystone markings), and add a touch of Roof Brown for later repaints
(Shadow Key), and more for even later repaints (Plain Keystone).
The best decals for this conversion come from the G31e Middle
Division set, which will do the Shadow Key (1954 to 1960), and
Plain Key (1960 to 1968) schemes. Others are less perfect substitutes.
- For all but newly-shopped gons, weather the hell out of the
model, and sprinkle lots of trash on the floor. Gondolas were
more beat-up than any other type of freight car. A liquid wash
(1 part brown/black to 5 parts thinner) painted into the junctions
between ribs and sides, and in the end corrugations, then partly
cleaned up simulates dirt, rust and soot collection. Wash, spatter,
splotch, then spray the inside with mixtures of Rail Brown, Black,
Roof Brown, Rust, and/or Orange in varying amounts to simulate
rust and staining by loads and heat from hot steel. Overspray
the exterior with heavily thinned freight car color, perhaps with
a few drops of white or gray added. This simulates paint fade
and blends everything together. Overspray with Dullcote. You're
You can save considerable aggravation by constructing
models three or four at a time. It gives a greater sense of satisfaction
to finish off a few models at once, and you save effort decaling
and painting in groups.Go back to the G31 page
©1999 Elden Gatwood
Go back to the G35 page
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