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August 2003 - Page 20

Modeling a PS-4750 Covered Hopper
by Ken Edmier
Photos by the author

Kadee delrin insulating screws. Drill and tap a #56 hole through the coupler cover and assemble. Trim the screw flush and then remove the screw. Make a saw cut through the coupler box cover only, about halfway between the truck bolster and the screw hole. Trim about two threads off the screw, reinsert, then tighten and glue the remaining part to the coupler box assembly. Fill the hole above the screw with green putty, along with the two outside holes on the top of each coupler box assembly. Drill a #78 hole in the each end of the coupler cover for the future placement of coupler lift bars. The coupler box assemblies can now be attached to the body. If you are planning to use Kadees self-centering trucks, remove the truck posts on the bolsters at this time.


or some reason, I like the Frisco. Since I was only 14 years old when the Frisco became part of the Burlington Northern, I never got to experience the Frisco firsthand. I have always wanted to model a Frisco car, so when I came across this Frisco PS-4750 covered hopper, I knew I had my car. SLSF 79866 was built in June of 1977 by Pullman Standard, lot number 9944 for 300 cars, series SLSF 79800-79999 and 81100-81199. After the BN merger, these cars were renumbered BN 445700-445999. Some of these cars just had the reporting marks changed, while others received new BN green paint. These cars can now also be seen in BNSF paint, as series BNSF 429469-429975. (Note: this BNSF numbering series also includes the 1974-built Frisco PS-4750s.) The InterMountains model is based on a 1978 Soo Line prototype with truckmounted brakes. The main differences between the InterMountain model and the Frisco car is in the body-mounted brakes and discharge-gate detail. Both cars feature an overhanging roof and a Morton roofwalk, so a lot less work is required then for the earlier phase Santa Fe PS-4750 covered hoppers featured in the November and December 2001 Model Railroading. Starting with an undecorated model, trim away the air-tank supports on the brake end and the circular lip around the brake line openings on each end. Fill the circular openings with styrene plug trimmed from the roof sprue, filling any gaps with Squadron Green Putty. Drill a #50 hole on each end on the lower part of the now-filled circular opening. The inner triangular gussets need to be trimmed to match the smaller outer gussets. I modified the coupler box covers to include screw-on coupler boxes using

Brake Gear and Hopper Details
The linkage that links the brake cylinder with the trucks actually runs through cutouts in the hopper bays under the center sill. Start by drilling a #63 hole just above the intersection of each hopper bay with the center sill. Then, enlarge each of these holes with a #52 drill bit. Using a sharp #11 blade, enlarge each hole into a trapezoidal opening, 15 " wide at the bottom of the center sill down to 12 " wide, by approximately 5 " high. The center sills bottom lip was represented using .010 x .030 strip styrene attached to each side of the center sill, making sure the ends of each strip near the hopper bays have a small taper. Form two brake levers from a 3' long piece of .020 x .040 strip styrene and round each end. Drill two #78 holes on one lever, one in the center and the second hole toward one end. Drill three #78 holes in the second lever, one in the center and one on each end. With the body upside down and the brake end on your left, secure the brake lever with

Getting Started

three holes 9" away from the brake-end hopper bay, centered on the center sill and with the top slightly angled toward the brake ends. The slack adjuster with clevis came from an Eel River Models freight car detail set with a second clevis from Precision Scale (PSC) secured with cyanoacrylate (CA). Attach a .015 brass wire to each clevis. The slack adjuster is located between the center hopper and the brake-end hopper and is installed with the PSC clevis mounted about 24" from the center hopper. Trim the end of each brass wire and bend each end 90 and place in the center hole of each brake lever. The linkage should be spaced about 1" above the center sill; small styrene shims were used inside of the hopper bays to obtain the proper spacing. From the outer hoppers to the trucks, use .015 brass wire to represent the linkage to the trucks. Insert in the end top hole on the left side and the bottom hole on the right side and run to a #78 hole drilled on the top of each bolster. Form four 21 " long brake-rod safety brackets from .015 x .042 brass strip, bent 90 3 " in on each end and one 27 " long bracket, bent 90 6 " in on each end, and place on the center sill per the Figure (see Photo 1). The Frisco car has short-track discharge gates, probably made by Enterprise. The InterMountain discharge gates are Youngstown which feature a long track with the opening socket in-between and at the end of the gate tracks. The Athearn discharge gates (called outlet covers by Athearn) are a better starting point for modeling the Enterprise discharge gates. Start by trimming the mounting pegs off the Athearn discharge gate along with the gate tracks right after the opening socket. Two .060 channels are placed on the each side of the discharge gate. The channel must first be notched to fit almost completely around the



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