One distinction of the demonstrator’s construction was its carbody rivet strip arrangement.  The rivet strips on the sidewalls near the four portholes are different than on subsequent production models.  Fortunately I found this change to be very doable, although great care was needed.

In the photo below, the vertical rivet strips marked with a blue arrow had to be removed.  The red arrow points to a yellow line that represents a rivet strip that must be added.


I carefully removed the lower strips first with a Micromark chisel (Micromark), taking little material with each left and right pass (it is best to remove in small amounts) while staying away from the horizontal strips.  Then I pushed a No 10 (curved) blade into the end of the vertical strip where it meets the horizontal one (top and bottom).  Next, I used the chisel again to clean up more strip in the up and down direction.  The No 10 blade cut helped stop the chisel movement from going too far and damaging the horizontal strip.


As the picture below shows, I protected the horizontal rivet strips with tape prior to sanding the vestiges of the chiseled vertical strips.  I progressively sanded 220, 320, 400, and 600 grits.


The same procedure was done for the upper vertical rivet strips (doing one car body side complete took about 45-60 minutes).  At this point I scuffed all flat surfaces with 600 grit for better primer paint grip.


The vertical rivet strip was made with .010”x.030” wide strip styrene.  After the cement dried, I sanded the top face of this strip to decrease its thickness to about .005”-.006”.  This strip looks too wide in the picture, and even so in real life, however its width at .030”-.031” is the same as the moulded vertical strip above it.  I think this is an illusion due to the missing rivets and white colour on black body.  These rivets will be from .008” diameter Archer decals.  I will not apply them until the decal stage as I am concerned about lifting them when I peal off the Imitation Gold stripe masks.  I will need to fine-tip brush paint these black rivet heads after the decals are set, but before the flat coat.


For me, so far, all this effort was worth it.

FT Tidbit:  I believe that the rivet strip arrangement around the four portals was altered for production locomotives because it easily accommodated an EMD factory option for large illuminated side number boards.  Most Model F/FT’s did not have these, so a plain panel was installed instead.  Railroads that had the large side number boards on their Model F/FT’s were the AT&SF, D&RGW, GN (some), MP (some), StL&SW.