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  • Modeling a Frisco PS-4750 Covered Hopper

    by Ken Edmier

    Photos by the author

    Model Railroading - August 2003 - Page 20

    For 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 InterMountain's 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.

    Getting Started

    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 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 Kadee's self-centering trucks, remove the truck posts on the bolsters at this time.

    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 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.

    Model Railroading - August 2003 - Page 21

    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 opening socket. Cut the channel so that it has an even angle with the front of the Athearn gate and extends 15" beyond the opening socket. Drill a #78 hole in each channel near the angled end at the front of the Athearn discharge gate. Secure with the channel placed around the opening socket and with the channel continuous on the bottom side of the gate (see Photo 2).

    The Athearn discharge gate is too wide for the InterMountain hopper bays, so each discharge gate needs to be narrowed 10.5". I used a NWSL Chopper, splitting the gate in half, then removing the 10.5" from one side. Attach one side of the gate with the channel just protruding from the front and side of the hopper bay, then follow with the opposite side. Trim the gates as necessary to get the channels in the correct location on the hopper bay or leave a gap between the gates and fill with green putty.

    The prototype gates have a piece of flat stock on the front and sides just above the channels. The locking mechanism also mounts to the back of this flat stock. Make two 54 " long strips for each hopper side from .015 x .040 styrene strip. Before mounting, notch one end of each strip to clear the opening socket. The notch is approximately 3" from the end, 1.5" deep and 12" long. Mount the strip so the top corner, away from the discharge end, is even with the hopper bay corner and trim at an angle following the profile of the hopper bay. Then, make three 60" long front hopper strips using .015 x .040. Center the oversized strips matching the ends with the side strips and secure in place, then trim the ends to match the side strips and use green putty to fill any gaps. I simulated the manually locking mechanism for each gate with a 42" long piece of .025 styrene rod. Trim and bevel each end to sit on the angled side plates just behind each discharge gate (see Photos 3 & 4).

    Model Railroading - August 2003 - Page 22

    According to NMRA standards, the recommended weight for the finished car should be 4.75 oz. Since the bottom of the hoppers have the openings for the brake linkage, I created a false bottom in each hopper with .040 styrene sheet, cut 6' x 6', and .100 channel in-between each hopper, secured with CA. The A-Line weights were secured with Elmer's® white glue. The weight was covered liberally and allowed to dry for a few days. Then, the two bay dividers were installed into the slots on the inside of the body (see Photo 5).

    Plano Roofwalk

    As you probably know by now, I am a Plano addict (I am told that there is no known cure.) Plano produces a perfect round-hole (Morton) roofwalk set for the InterMountain car. Start by filling the holes in the roof for the kit-supplied roofwalk with green putty. Do not fill the holes located next to the roof trough as these are for the hatch-cover hinges.

    Follow the Plano instructions for marking the pilot points using the Plano-supplied templates and T-pin, except for the riser #3 locations. The risers under the roofwalk extension need to be both #3s. On the crossover frame drill template, I used only the four inner hole locations. After removing the template, I marked the four outer holes aligned with the inner points right on the edge of the center-raised center section. After all the pilot points had been marked, each pilot point was drilled with a #78 drill bit.

    Install the roof, making sure it is mounted with the locator holes for the hatch hinges on the left when looking at the brake end. Fill any gaps where the roof meets the car ends with green putty.

    The InterMountain kits come with two different sets of hatch covers. Since Pullman-Standard switched from ribbed to smooth hatch covers sometime in 1977, I was unsure which style of hatch covers the cars had when built. Jim Kinkaid was kind enough to look at builders photos and confirm the cars were delivered with ribbed hatch covers. Install the ribbed hatch covers and hinges.

    Install the risers per the Plano instructions, following the numbers on the template except for the risers under the walkway extension, as previously noted. Use two #3 risers under each walkway extension, shortening one leg as necessary. Then, install the crossover frames, making sure to keep the crossover platform centered (see Photo 6).

    End Detail and Assembly

    Starting with the brake air tank, remove the plastic air lines and drill two #78 holes where the old plastic brake lines were attached to the tank. Make two triangular styrene brackets from .030 x .125 styrene strips using a NorthWest Short Line Choppers 60° angle. Then remove just a little bit of the angle tip with a razor blade before securing to the tank. Mount the tank assembly on the left side of the brake end. Use a piece of .020 x .040 styrene strip, trimmed to fit, to represent the vertical piece of steel running alongside the left tank bracket from the bottom lip to the slopped end-sheet.

    Model Railroading - August 2003 - Page 23

    The control valve is mounted on an S-shaped bracket. Make the first part of the bracket with 3/64" styrene angle. Trim one end to a point to fit a #68 hole and make the angle approximately 18" long. After drilling a #68 hole on the left side of the far right triangle bottom sill bracket, secure the angle in place. Make the top portion of the bracket from .020 x .080 styrene strip x 15" long and secure to the top of the angle away from the air tank.

    The Atlas brake cylinder is mounted on a pad that is placed next to and even with the top of the coupler pocket and supported with two triangular supports from the coupler assembly. Make a pad from .020 x .156 styrene strip, cut 12" long, and mount on the left side of the coupler assembly. Then make the two triangular styrene brackets from .030 x .125 styrene strips using a NWSL Chopper's 45° angle, removing just a little bit of the angle tip with a razor blade before placing under the pad and securing in place. Trim off the brake rod on the brake cylinder and drill a #72 hole in the back and front of the brake cylinder and secure to the pad, centering between the two vertical uprights for the brake mechanism on the end ladder assembly. There is a small round tube located between the brake cylinder and the vertical piece of steel running alongside the left tank bracket. Make a 9" long tube from .035 styrene rod and mount in place.

    Trim the InterMountain control valve by removing the top two protruding pieces and trimming one side to approximately match the prototype control. Determine the orientation by finding the side that has three blocks and drill four #78 holes on the center block in two rows of two. Mount the control valve on top of the S-bracket with the four holes facing the brake air tank. Install two pieces of .015 brass wire from the air tank to the top two holes of the control valve and run one piece from the back of the brake cylinder to the lower left hole on the control valve.

    Make a new 5' 9" long vertical brake beam from .020 x .060 strip styrene. Next, drill two #78 holes, 3" and 21" from the bottom for the brake linkage and the brake cylinder. Using .015 brass wire, form a small loop through the second hole on the vertical brake beam and feed the wire through the hole on the front of the brake cylinder and then secure the vertical brake beam in place vertically. The brake linkage line, made from .015 brass wire, runs through the bottom hole and connects to the brake lever in front of the brake-end hopper.

    The horizontal brake beam on the prototype runs from the body to the end ladder assembly, with the top of the angle level just above the brakewheel. Make a new horizontal brake beam from a 4' 6" long piece of 3/64" angle. Attach this horizontal brake beam to the body and the vertical brake beam, making sure it will match the end ladder assembly.

    The InterMountain kit includes the end pieces of the train air line, including the angle cock and air hose. Place the non-air-hose end into the modified center opening, trimming if necessary, and mount using the support mounted on the train air line in the hole provided and to the lower part of the coupler box assembly. Then, run one piece of .015 brass wire from the lower right hole on the control valve to the top of the train air line above the support mount (see Photos 7-9).

    The Plano roofwalk set includes the coupler platforms. Drill two new #76 holes for the Plano platforms, using the end holes on the metal template, on each end ladder assembly. Trim the bottom of each interior vertical support to clear the coupler platform. Secure the platforms on the proper ladder assemblies. The horizontal brake beam mounts to a small pad on the brakeend ladder assembly, mounted behind and just above the brake mechanism. Install a 15" long piece of.020 x .080 strip styrene to represent this pad. Install the kits bottom ladder rungs and long end grabirons and drill a #78 hole in each coupler lift bar bracket. Before installing the brake mechanism, trim away the molded plastic chain (see Photo 10).

    Model Railroading - August 2003 - Page 24

    The ladder braces have a row of small rivets on the angle part that faces outward. Starting with the brake end, attach one left and one right ladder brace by placing the rectangular end of the brace in each locator hole on the end of the body. Make sure the long angle section of the brace is installed on the inside with the angle facing down. Trial fit the brake-end ladder assembly, trimming the brake beam if needed before securing in place.

    Two angles are mounted from the brake cylinder mounting pad toward the end ladder assembly on both sides of the vertical brake beam. Using a .100 styrene channel, cut to 3' 3" in length and then split the channel in half, creating two angles. Attach with both angles facing away from the vertical brake beam with the top of the angles level, ending just below the end ladder assembly.

    A trapezoidal-shaped bracket is mounted on the end ladder assembly for the brake chain to run through. Make two pieces from .015 x .100 strip styrene, cut 15" long and trim one corner of the narrow ends at a 30 angle. Use a single .040 x .040 strip cut 12" long and place in-between each of these trapezoidal pieces on the long side and glue together. Secure to the bottom of the end ladder assembly and to the front of the angles running from the brake-cylinder mounting pads. The bottom of the bracket needs to be flush with the bottom of the coupler pocket.

    Chain is used from the brake mechanism to the vertical brake beam. Using a small piece of .015 brass wire, make a small U-shaped hook and place through the last chain link. Place the hook around the vertical brake beam and attach with CA. Run the chain to the right side of the brake mechanism, running through the trapezoidal bracket and the coupler platform, trimming as necessary to let the chain hang loosely, and secure with CA. Place a .015 x .100 x 12" long piece of styrene strip on the bottom of the bracket extending to the coupler pocket. Then, make a small pad using .010 x .060 styrene cut 9" long. Place on top of these two angles, just behind the vertical brake beam towards the body.

    Now attach the brakewheel to the brake mechanism. Before installing the diagonal brace with the retainer valve bracket, remove the tall bracket for the control valve. After installing both diagonal braces, make a 12" long vertical brace from .020 x .080 styrene strip. This is mounted vertically on the inside angle of the diagonal brace and against the bottom of the control valve bracket. Install the retaining valve with air line, re-bending the air line as required.

    Model Railroading - August 2003 - Page 25

    The air release rods run from the control valve to brackets underneath the ladder braces. Form two brackets from 010 x .030 styrene strip, each 9" long. Drill a #78 hole in the end of each bracket and mount on the back of the ladder braces below the middle set of rivets. The release rods are made from .008 wire; form a small loop at one end of each release rod by wrapping it around .025 styrene rod. Place each rod through the bracket and run to the bottom of the control valve. Finally, install the side ladders.

    The non-brake end is a lot simpler. Install the train air line, ladder braces, end ladder assembly, diagonal braces and side ladders.

    Final Details before Painting

    Install the shaker brackets to each hopper bay. Install an eyebolt in each of the coupler lift bar bracket holes vertically after bending the eyebolt just behind the eye. Form each coupler lift bar by bending the end straight, then re-bend with a smaller protrusion to place in the coupler pocket cover hole and then rebend to create more of an offset. Install each coupler lift bar through the eyebolt and in the end of the coupler pocket cover.

    Secure the roofwalk in place with Cyanopoxy. I used pieces of .040 styrene strip as a spacer to make sure the roofwalk was evenly spaced from the raised hatch area. After securing the crossover platforms in place, install the roof grabirons to the roofwalk. A tack board is placed at the bottom of the first panel on each side. The tack board can be seen directly below the first two car numbers on each car side. The tack boards are .015 x .080 styrene strip, 9" long (see Photo 11-15).

    Model Railroading - August 2003 - Page 26

    Paint and Decals

    This lot of Frisco covered hoppers was delivered in gray paint with black used roughly below the sidesills. Start with a coat of primer gray, thinned about 30 percent with 70% isopropyl alcohol. After priming, paint the car with thinned SP Letter Gray.

    Due to the open ends, I masked the car sides and ends across the truck bolsters and sprayed the underside and hopper bays black. Then, with a fine brush, everything below the diagonal braces was painted black, including the bottom two steps of the end ladders. After the paint had dried, it was sprayed with Testors Glosscote before decaling.

    Oddball Decals #371 was used for the majority of the black lettering. The reporting marks with this set are too small and not the correct font. I used the 10" letters and numbers from Microscale 87-632. The small black lettering to the left of the warning decal came from Microscale 87-444. The white lettering for the hopper bays, center sill and jacking pads are from Microscale MC-4276 along with the lube plates and yellow end lettering. The ACI plates are from Microscale 87-2. The end reporting marks and brake lettering came from an old Herald King H-463, but the brake lettering can be pieced together from Microscale 87-2 and the end reporting marks from the Oddball set. Decal setting solution was applied after setting each decal in place. When finished, the car was sprayed with flat clear lacquer to seal and protect the decals for weathering (see Photo 16).


    In looking at the prototype, three distinct weathering patterns can be seen the fading of the gray paint to white, the black streaks on the car sides, and the underbody/hopper bay grime. Starting with the fading, I sprayed the roof and the car sides lightly and spottily with thinned Reefer White. Use a wet Q-tip® with Champ decal setting solution to remove the white, as desired, for a splotchy fading pattern (see Photo 17). (Note: Champ decal setting solution will remove the decals if rubbed too much. The clear lacquer provides better protection than Dullcote, but still use sparingly.)

    Model Railroading - August 2003 - Page 27

    Next, apply a light grime wash, one part Railroad Tie Brown and one part Weathered Black to the side and ends of the car using the Q-tip weathering technique. Add two parts water to the grime paint and apply with a small brush to one panel at a time. Then, use a dry Q-tip to remove the wash, waiting only about ten seconds. A wet Q-tip with decal setting solution can be used to remove more of the wash, but be careful around the decals (see Photo 18 & 19).

    The last weathering step is to airbrush the hopper bays, underbody, and to dust the rest of the car with Railroad Tie Brown, thinned about 30 percent with 70% isopropyl alcohol. Paint the end loops of the air release rods white, the glad hands and angle cock on the air hoses silver, and drybrush a little black on the tack boards. Then, lightly drybrush the chain below the brakewheel, the glad hands and angle cock with Rust. Seal with Testors Dullcote.

    Kadee's self-centering trucks were substituted for the kits trucks and wheelsets. The wheelsets were removed, painted Rust, and the treads polished using a Dremel tool to simulate shiny metal. The wheelsets were then drybrushed with a little Railroad Tie Brown to give each wheelset a different rust/weathering pattern. After removing the trip pins from Kadee's #58 couplers, the trucks and couplers were airbrushed with one part Rust and one part Railroad Tie Brown. Install the couplers, adjusting the coupler height as necessary. Highlight the trucks by drybrushing with a little Rust, especially on the springs and journals. Before installing the wheelsets, paint the brakeshoes on the trucks with grime and install the trucks per Kadee's instructions.

    I now have my Frisco car.

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