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Owl Mountain Models

F-50-Series flatcar kits (2000-Series) - HO Scale

OwlMtModels is proud to introduce our new F-50-Series Kits made in the U.S.A.!

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Second Run Coming Soon!

News for Sept 2017! - 'Green Flags' for the Flatcars

We're amazed and the massive responce to our first HO scale kit. We are currently sold out and have a second run of the kits on the way. Please email us to reserve cars from the next run!

The new F-50-Series Flatcars have sold out with the closing of the reservations on Sept 15th, 2017! Click the photo above for more information and information about the following Section (Run) of the F-50-Series kit delievry. Please Email us for getting your Reservation in for the 2nd Run of kits!

Ordering F-50-Series Models

SP_43745_Sac-B1sml
Kit 2002 finished as SP 43745, an ex-PE F-50-9 transferred to the SP along with 99 other cars in 1928.

All kits contain all parts needed to complete the model for running on your HO railroad, including: Trucks, wheels, Kadee #156 couplers, screws, weight, decals, brass castings (stirrup steps, brake wheel, and roping staples) and wire to make the brake rods, grab irons (jig provided), and brake staff. Both AB & K-brakes are included and can be applied to the model to suit whatever era is desired. - Note: In this photo the Underframe plastic sprue is gray plastic, production kits will have this part in the same brown as the sides and detail sprues. The Deck will be in gray plastic as shown.

Kit #2002 - F-50-5,-8,-9 w/T-section Trucks

Correct for 1650 prototype cars, built 1916-1924. White decals provided for SP, PE, NWP, T&NO, (GH&SA, LW) and SPMW. A number of these cars were assigned to SPMW service, at least 181 by 1956 in many assignments.

Kit #2002 - $39.95

Kit #2003 - F-50-10,-12 & Retrucked Cars w/U-setion Trucks

Correct for 950 prototype cars, built 1927-1929 for SP, in three number series. White decals provided for SP and SPMW. A number of these cars were assigned to SPMW service, at least 36 by 1956.

Kit #2003 - #39.95

Kit #2004 Post-1958 SPMW Gray with Black Lettering - with T-section Trucks

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Correct for F-50-5/8/9 class prototype cars repainted in SPMW light gray after 1958. Totaling about 181 assigned to MW service by 1956, many lasting into the 1960s and 1970s in MW service.

Kit #2004 - #39.95

Kit #2005 Post-1958 SPMW Gray with Black Lettering - with U-section Trucks

Correct for F-50-10 & -12 class prototype cars repainted in SPMW light gray after 1958. Totaling at least 36 cars by 1956, many lasting into the 1970s.

Kit #2005 - #39.95

Prototype Design and Service History

Southern Pacific's earliest flatcars can easily be traced back to the building of the transcontinental railroad in the 1860’s. These wooden cars evolved and grew larger until the first steel framed flatcars were developed in the early 1900’s. E.H. Harriman took over the Southern Pacific (SP) in 1901 and developed the “Common Standard” for structures, engines, and rolling stock for the five railroads he controlled at that time. SP and Union Pacific (UP) designs, along with their subsidiary roads, fell under this standardization plan of the “Associated Lines.” The first Common Standard flatcar was the CS-35-A of 1903. Other early designs included the F-50-1,-2 and -3’s, with the F-50-4 as the last true Harriman “Common Standard” flatcar design.

After the Supreme Court break-up of the Harriman roads back into their individual identities in 1913, the CS numbering system continued, but the SP and UP settled on a simpler classification system of car type: “F” for flatcars, “50” for 50-ton nominal capacity cars, and then sequential numbering for that weight and car type. So F-50-1 would be the first class of 50-ton flatcars designed in this system. Designs after 1913 for UP and SP diverged, but retained the F-50-type series nomenclature for many years. The SP finally abandoned the naming system around 1965 when they stopped designing most of their own freight cars and bought “off the shelf” designs from other car builders.

After the 1913 divestiture, SP’s design department improved the F-50-4 class with the F-50-5 in mid-1916. The initial design of the F-50-4’s, with the Bettendorf single I-beam underframe, was found to be inadequate for regular service. Under loads, the underframes failed regularly by fracturing along the section of the I-Beam that was cut and bent to create the “Fishbelly” profile between the trucks. The new production F-50-5 and later designs used a built-up double beam centersill underframe.

F-50-5,8,9_Roster_Table1
The last of 50 NWP F-50-5s, NWP 4499, built from Kit #2002 and lettered in a typical 1920s NWP scheme. The car shows last being reweighing in Willits in July 1921. In later years NWP's lettering changed to be more like SP's standard freight lettering to comply with AAR's later recommended reporting mark practices.

F-50-6 & -7 designs were very different from the previous classes, but the F-50-8 and -9 designs went back to nearly identical designs to that of the F-50-5. Table 1 summarizes the F-50-5, -8 and -9 cars built during this era. The distinguishing feature of all these flatcars was the overhanging deck with wooden blocks and steel angle iron to support the overhang. This feature is often very identifiable in photos, even in 7/8 front views of trains. This OwlMtModels series of kits replicates this deck block feature, unlike any other HO-scale flatcar on the market today.

Of about 7400 SP and subsidiary railroad flatcars built with this deck design, this OwlMtModels #2002 kit replicates the F-50-5,-8, and -9 designs of 1650 prototype flatcars; the “sister” #2003 kit replicates the later F-50-10 and -12 series of 950 cars (with U-section trucks), and our upcoming #2001 kit represents the 1500 prototype F-50-4 flatcars.

F-50-5,8,9_Roster_Table1
(Click Images for Full Size View)


The SP 38892, an F-50-8 class car made with Kit #2002 was one of the last group of surviving cars from PE 3614-3763 group (150 cars) which were transferred to the SP in 1951. The PE's cars were absorbed into the SP numbering system in three groups starting in 1928 along with the two CP cars. The second group joined the SP ranks in 1940, and the last group in 1951. The cars in each of these groups were repainted as the car's next regular shopping and reweighing came due, which was every 48 months (4 years).

The F-50-4, -5, -8, -9, -10 and -12 cars were the mainstay of the SP's fleet until after World War II, when the new F-70-series cars were being built in large numbers. Many earlier cars were renumbered as they continued in service (Table 2). Over the years the F-50 cars were modified (either permanently or temporarily) for various special loads or services. Temporary mounting of racks allowed shipment of sugar beets, pulpwood, and wood chips, while more permanent modifications included rails for copper anode plates, log bunks, and many maintenance-of-way (MOW) variations for supplies, ditchers, ballast spreaders, and special deck cradles for moving car wheel sets between shops.

Renumbering_of_F-50-5,8,9_Cars
For additional information, see Southern Pacific Freight Cars Vol 3 Automobile Cars and Flat Cars by Anthony W. Thompson, Signature Press, 2004.


Many other SP F-50-series flats were reassigned to maintenance-of-way (MOW) service, such as SPMW 1413, an F-50-5 converted for Supply service in October 1952. This model from Kit #2002 with supplied T-Section trucks, K-brakes, and white SPMW decals.

Many of the F-50-series cars continued to be used in SP and T&NO's MOW rosters from 1958 until about 1980 with the change to light gray paint and black lettering. These later MOW cars can be modeled with our #2004 & 2005 kits which has black SPMW decals instead of the regular white set.


SPMW 2054, an F-50-10 converted to MW service in Oct 1954, sports a worn post-1958 gray paint job with black lettering as it would have appeared in the late-1960s. This model was made from Kit #2005, with the black SPMW decals, AB-brakes installed and U-section trucks.

Considering the F-50 series of cars lasted in various forms for 60-70 years, they truly have an impressive legacy.

Relavent SPMW Roster Jan 1956 for F-50-series cars.

New Design Features

Narrow Draftgear

One area where we're pushing the limits with the new F-50-series cars is in the draftgear and endsills. During our development phase of this project, we observed that the F-50-series models are much smaller than what we're used to seeing in the hobby with the bigger boxcars (even WWI era USRA cars). If we put a full 1/4" wide coupler slot in the end of the car for a standard HO NMRA-Kadee box and reproportioned the other details around it, then the endsills looked very over-scale compared to prototype photos. We decided to try something new in HO scale.


SP 38909's end sill with 'near-scale' draftgear-shank opening and Kadee-156 coupler.

In 2013 we converted several test boxcars to use this new narrow draftgear-shank opening design. We 3D printed our first pilot model and tested it extensively in-service at a large model railroad club layout. Various positions in the train were tested, including putting the pilot model directly in front of a helper shoving on 40 cars on a 2% grade! The 3d printed pilot model did amazingly well in these tests that were designed to purposefully find problems with the design concept of the car.

We found that these cars performed very well and also worked down into tight 18" radius industrial spurs without any issue. The narrower coupler shank opening only became an issue when attempting delayed magnetic uncoupling on tight (18" Radius) curves. The Kadee-156 coupler heads and knuckles actually have enough freeplay (slack) in them that cars can stay coupled down to very tight radius (almost to the point of the corners of the two models touching).

We felt that in most operating conditions for the cars these days, the narrower shank opening combined with the extra 'slop' in the mating areas of the Kadee Scale Head couplers will perform well. Modelers running into any issues from the narrow draftgear opening can easily create more movement by filing extra width into the sides of the striker opening section of the box and continue until the needed draft gear movement is achieved.

Weathering Tips, Techniques, & Addition Information

F-50-5,8,9_Roster_Table1
T&NO 22419, an F-50-5 built from Kit #2002, about 1950 after changing from LW to T&NO reporting marks. Click on link below for Additional Information on subsidary roads that purchased F-50-5,-8, & -9 classes.

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