Most flatcars built under government allocations during WW II were 50-ton cars, but cars built to the AAR 70-ton design were authorized for several railroads. The Greenville Co. delivered 350 70-ton flats to the Pere Marquette early in 1943, numbered 16500-16849. A builder's photo showing one of these PM cars appeared in the 1943 CYCLOPEDIA and is repreinted in TRAIN SHED CYLCLOPEDIA No. 75. At about the same time, Pullman built 200 similar cars for the Atcheson, Topeka and Santa Fe which became class Ft-V Nos. 91500-91699. In 1944 the New York Central's Despatch shops produced 300 AAR 70-ton flatcars as lot 721-F, numbered 499300-499599, and these were soon followed by an additional 200 cars in the 499600-499799 series. Several other railroads acquired flatcars during this period which were dimensionally identical, and were probably of AAR standard design, but I have been unable to locate photos or other documentation to confirm this. These included CRP Nos. 101-200, DT&I Nos. 900-949, NYNH&H Nos. 17300-17399, and Wabash Nos. 25500-25549. Perhaps readers of PROTOTYPE MODELER can contribute photos of information on these cars.
Owing to their capacity and sturdy construction, many 70-ton AAR flatcars survived into the 1970's, and some are still in use. Shortly after WW II the Chesapeake and Ohio, which owned the Pere Marquette, integrated the PM's freight cars into the C&O roster by prefixing a "2" to their Pere Marquette numbers. The PM's 70-ton flatcars thus became C&O series 216500-21849. In later years, many of these cars were specially equipped for tractor- and auto-frame loading and other types of assigned service. During the 1950's the Santa Fe class Ft-V cars were fitted with pulpwood racks, and in this form most of them continued in revenue service for another twenty years. The Erie's 8000-series cars kept their original numbers following the Erie-Lackawanna merger. Later, however, some cars in this group were renumbered when equipped with end bulkheads, racks for truck frames and boats and other modifications. Some of the New York Central's AAR 70-ton flats also were renumbered when assigned to such special service as aluminum cable loading, and most had thier nominal capacity increased to 154,000 lbs.
There are no HO scale flatcars which resemble the AAR 70-ton cars in dimensions and appearance. Athearn's 50' flatcar comes the closest, but it's too short, has only thirteen stake pockets, rides too high on its trucks, and lacks an overhanging deck. By combining and reworking parts from Athearn's kit, however, it's possible to construct a reasonably accurate model of the AAR standard prototype, an approach that's especially appealing since Athearn parts are sold separately and are inexpensive. The first step is to splice parts of two Athearn 50' flatcar bodies together, as shown in the photos, producing a carbody with fourteen stake pockets that scales just a few inches shorter than the AAR prototype flatcar. After the two body sections are cut precisely to length with a razor saw, they're cemented together with 2" x 12" styrene reinforcements behind the joints in the sides (but not the floor), and acrylic filler applied to the external seams as necessary. The floor weight is then shortened with a hack saw to about 33 scale feet, checked to make sure it's precisely flat and straight, and secured to the center of the carbody with ACC.
To make the model ride low on its trucks like its prototype, the truck bolsters must be mounted directly to the underside of the car floor. First, an amount equivalent to the thickness of the floor weight is removed from each truck mounting stud. Then the bolsters and coupler pockets are cut from an Athearn underframe, filed smooth where they fit against the floor, and cemented in place. After the cement is dry, the openings in the end sills are filed so they line up with the inside surfaces of the coupler pockets. At this point, it's advisable to mount the trucks temporarily, using No. 2 X 3/16" screws, and check for wheel clearance and coupler height, making adjustments with Kadee shim washers as necessary.
The underframe is built up by removing the middle body bolster from one Athearn center sill and splicing in a section cut from another center sill, using the center spines of the Athearn upper underframes to strengthen and align the joints. The new underframe should have only two body bolsters and should fit just inside the truck bolsters, as shown in the photo. The small underframe cross-members can be left in place, but I simplified matters by cutting them off at the center sill since they're invisible when the car is on the track anyway. I cemented two plastic pads the same thickness as the floor weight between the ends of the weight and each truck bolster to support the ends of the center sill, and then attached the underframe assembly to the floor weight with ACC.
With the underside of the car complete, detailing the sides and deck comes next. The prototype cars had pressed-steel stake pockets rather than the cast steel type represented on Athearn's model, but this discrepancy can be corrected. First, the lower edges of the stake pockets are cut off at an angle. Then the cast ribs on the front faces of the pockets are filed off, and the vertical corners rounded. Finally, the openings in the pockets are enlarged with a tapered knife blade and a square patternmaker's file. The stake pockets then take on the appearance of pressed-steel pockets, though they're still not a perfect match for those on the AAR cars.
Turning to the deck, the steel plates over the truck bolsters and draft gear pockets should be outlined with a knife blade or scriber and the deck seams inside these areas filled with putty, sanded smooth, and primed. Sections of 4" x 8" styrene strip stock are then cemented to the edge of the deck between the stake pockets to represent the deck overhang (note that there is no overhang at the extreme ends of the car).
The inside edge of each piece shoud be rounded slightly with a file or scraper to ensure a snug fit in the corner where the cast-on decking and the car sides come together. Whe the cement is dry, these extension pieces are filed and sanded flush with the top of the existing deck and the planking lines extended across them with a knife blade and triangular file. At this time, the entire deck can be gouged and beaten up with knife blades and file to represent an appropriate degree of wear and tear. Then the steel-plated areas are masked and the deck lightly sanded witjh very coarse (50 or 60 grit) finishing paper to impart a "wood grain" effect. Next, four end stake pocket holes are drilled through the deck with a 1/16" drill bit and made square with a patternmaker's files. These holes are located just inside the end sills and about two and a half scale feet on either side of the car's centerline. A semi-circular brake wheel recess is also cut into the edge of the deck at the "B" end of the car to clear the brake wheel when it's in the lowered position to accommodate overhanging loads.
Only a few details now remain to be added. A brake wheel mounting can be fashioned from a piece of styrene at the lower edge of the end sill. The same thing can be done for an eye bolt at the upper edge. The Cal Scal No. 289 brake wheel can also be attached to its .020" brass wire staff at this time but should not be installed until after the car is painted and lettered. The same goes for the Grandt Line No. 5129 or 5130 sill steps to reduce the risk of damage in handling. Uncoupliung levers are shaped from .015" bras wire and mounted in Detail Associates No. 2206 eye bolts. Route card boards, towing eyes, a brake retainer valve, and similar small details are added as appropriate for the particular prototype being modeled, after which the model is ready to be painted.
Sides and ends were painted black on the Erie and Pere Marquette cars, freight car red on the Santa Fe and New York Central versions; some NYC cars were probably jade green in later years. Underframes and trucks were usually black when new and the same color as the sides on repainted cars. Decks should be painted to resemble creosoted wood and weathered to suit. Appropriate decals for road names, reporting marks and numbers are available from both Walthers and Champ for all the prototype cars described here. Data from Microscale set No. 87-01 is recommended, as it's very close to scale size.
At least a few of your flatcars should be modeled withoput loads, as movements of empty flats to and from loading sites are fairly common. Flatcar loads are a modeling challenge in themselves, however, since they are often more interesting than the cars themselves. The AHM tank trailers on my Santa Fe car are no longer available, but similar ones are currently offered by Ulrich and Eko. Chooch makes the canvas-covered machinery loads on my Erie car, while the wooden crate was fashioned from scrap and lettered with decals from Walthers No. 1331 industrial locomotive lettering set. The plywood crates on my New York Central flat were suggested by those in the prototype photo, though I didn't try to model them exactly. The HO scale crates are basswood over solid wood cores, with a sharp pencil used to inscribe the seam lines and nail heads. The lettering is from scrap decals, and the cribbing and blocking is made of scrap basswood - I seldom throw anything away! The steel strapping that holds the crates in place is simulated with Chartpak pressure sensitive plastic border tape, which is available at drafting supply stores.