This article describes the modifications and changes made to an Athearn GP9 to make it more representative of those Rock Island units that have been rebuilt, some by Morrison-Knudsen, most by Precision National Corporation, at Paducah, KY. A model of a Silvis (shops) rebuilt unit would be similar, except for those early units e quipped with ox-yoke filter systems.
The Rock Island GP's (rebuilt and otherwise) do not have dynamic brakes Modifying The Athearn GP7 For The "Rock" (except for some ex-D&RGW units) so the dynamic brake housing blisters and fans were removed. The resulting hole in the top of the hood was plugged with.020" styrene, and the holes in the sides were plugged with the lugs from the dynamic brake blister moldings. The area was sanded smooth, and putty was used to fill cracks as needed.
The winterization hatch was removed and a pair of fans from another shell was placed in the opening. Sheet styrene was used to fill in the remaining hole. (See photographs for a closeup of the roof with these changes made.) The cracks were filled with putty and the area sanded. The molded on steam generator detail and the air horns were removed from the top of the short hood. A razor saw, knife, and file were used to remove the steam generator detail, and the area was sanded smooth. Next, the molded on drop steps were cut off; they are replaced with De tail Associates (DS1401) Drop Steps.
The molded on headlights were also cut away (actually, shaved and scraped until the area was flat) so that a Detail Associates (LT1004) Dual Early GP Headlight could be installed at each end. All the molded on lift rings were removed as were the molded on grab irons.
The pilot footboards were cut off, the louver sets on each side below the windows were shaved off and the area sanded smooth, (See photographs for views of the shell in the "everything off" condition.
A further modification is the change of the shape of the frame skirting, to more nearly outline the form of the Rock's Paducah rebuilds. The pilots were covered with.020" styrene. This necessitates body-mounting the couplers for ease or removal of the shell from the power unit. Lift bars were fabricated and installed with handrail stanchions.
Detail Associates Drop Steps (DS1401) were installed, as was their Sun Shades (SS1301), and Multiple Units Stands (MU1505). A Utah Pacific 5-chime air horn was installed in front of the cab, centered on the short hood.
My model is equipped with a "fire cracker" radio antenna. This is single strand hook-up wire, cut off to a short length. The insulation was peeled off until about 3/16" was left. A No. 75 hole was drilled at the rear center of the cab and the antenna was installed with about 1/16" of the base wire visible between the "firecracker" and the roof.
The "new image" blue and white color scheme was used. The body was first spray ed light grey, allowed to dry throughly, and then sprayed Reefer White (this will make the white color on the black shell a truer, more opaque, white). The white was allowed to dry over a few days' time, then masked and sprayed with blue.
The formula used for the mixing of the Rock Blue (officially known as Rhode Island Blue) is essentially that given in the Herald King L-540 Decal set: 2 parts of Floquil RR-56 GN Big Sky Blue to 1 part Floquil RR-ll Reefer White. About one extra drop or white was added to the 24 drop - 12 drop mixture just to lighten it a little. Since models are generally viewed under artificial light, the colors often need to be lightened a bit to give them the right "look. " Let your own preference guide you.
Refer to the "after" photograph for views of the finished unit with the modifications and added details. The unit was decaled with the Herald King L-540 decal set; the "bugboard" numbers were from a Champ set. Except for the Silvis rebuilt units, the "Rock" rebuilds have white numbers on a black background. The Paducah rebuilt GP7's have been assigned numbers in the 4425-4478 series. The Morrison-Knudsen rebuilds (there were 19 before the program was terminated) are scattered throughout the group. Check individual units if you want to do one of these; they were originally painted bright red with yellow ends and speed lettering but all have since been repainted in the blue "Rock" paint scheme. The Silvis rebuilt units start in the 4500's, going at the time this article was written, through 4543. Their horns are located behind the front set of fans, and some have "cold weather" window extensions. The top of the walk-way all around the long hood is blue and around the short hood is white. The drop step at the short hood is white on both sides; the drop step at the long hood end is blue on top, white underneath. The drop steps on this unit were mounted in the "up" position. Check recent issues of Extra 2200 South or Midwestern Rails for numbering of the Paducah/PNC re builds as well as for reference photographs of prototype units.