Freight Cars

by Dan Wexler

Part I -- Basic Concepts

This series of articles contains information about building model freight cars reflect their prototypes as accurately as possible. We will explore prototype equipment, including when it was built, how it was used, what types of equipment, such as trucks, would have been used for various loads, etc. We will also see which kits best model those cars.

The Three Basic Types of Kits

Type 1 I call these "Shake and Bake" kits. They include, but are not limited to, Accurail, Athearn, Con-Cor, Roundhouse, and Walthersí. You can easily assemble these kits with just a little bit of filing and a screwdriver.
Type 2 These "intermediate kits" include models from such builders as Intermountain, McKean, C&BT Shops, and Bowser. They have a one-piece molded body. You add the appropriate detail parts: grab irons, roof walks, and brake gear.
Type 3 Some manufacturers of "craftsman kits" are Ambroid, Tichy, Westerfield, and Sunshine Models. With these cars you open the box and you get unpainted and unassembled parts. They can be made of styrene, resin, or wood. Some kits donít come with trucks or couplers.

To a great extent, the price that you pay for a kit is in direct proportion to the amount of detail and prototype correctness you wish to achieve.

What's in a Kit?

Letís look at a kit and describe the parts and their purpose on the prototype car.

The Bottom

bulletThe largest component is the center sill, to which everything else attaches.

bulletNext is the brake rigging. The three major components are the brake cylinder, air reservoir, and the control valve (sometimes called the triple valve). For an in depth look at air brakes, refer to Model Railroader, November, 1994.

bulletThen come the truck bolsters--the flat round part that the trucks attach to. They may attach with a screw or a press pin. On a prototype car, the trucks are held in position by a pin mounted on the truck and fitted into a hole in the truck bolsters; they are not fastened to the car. General railroad practice paints the trucks the same color as the car body.

The type of trucks you choose depends a great deal on the era you model. For example, if you model anywhere from the 1920s to the 1950s you would use trucks from manufacturers such as Vulcan, Bettendorf, or Andrews, equipped with journal boxes, friction bearings, and 33-inch wheels. The Timken Co. introduced a modified truck equipped with roller bearings in the late 1930s, but they were not commonly used for another 20 years. Cars built or rebuilt after the middle 1960s all have roller bearing trucks with 33-inch wheels. This generally applies to cars used in interchange traffic; captive cars donít necessarily have to meet FRA. standards. Many of the modern hoppers, gondolas, and intermodal cars come equipped with 36-inch wheels, while auto racks and spine cars use 28-inch wheels.


bulletAt the end of the center sill are the draft gear (coupler pockets).

bulletAlong the length of the sill are the ribs whose primary job is to hold up the floor, and support the side sill.

Note that Athearn's chassis are a mirror image of the correct placement of the underbody detail. If you want your model to be accurate, you should carefully cut the parts from their molded-on location and move them to the same position on the opposite side of the chassis. (Or replace them with prototypical brake rigging, which is available in kit form. -editor.)

The Rest of the Car

bulletThe car sides attach to the side sill and contain the doors, ladders, grab irons, dimensional data, etc. Box car sides are often referred to as 8 or 10 panel. (Unless I state otherwise, I'm including refrigerator cars as box cars for the purpose of this discussion.) That refers to the number of riveted panels on each side of a car.

bulletThe major part of a box car side is the door. Doors can be constructed of wood or steel. A car usually has one or two per side. Cars with double doors have been around since almost the beginning of the 20th century and used mostly for hauling automobiles, and auto parts. Plug doors were introduced in the late 1940s to replace the hinged doors on refrigerated cars.

bulletThe box car roof may contain grab irons and ice hatch doors. There are many styles of roofs, which you can identify by the size and shape of the panels they are made of.

bulletAlso on the roof is the roof walk. This enabled brakeman to move from car to car to inspect the train or set the brakes. They could be made from wood or steel. New OSHA rules in the mid-1960s eliminated roof walks and with them the need to have ladders going all the way to the roof.

bulletThe ends of a freight car are designated as "A" or "B" ends. Except for a ladder, the "A" end is usually plain. On some extra length or extra capacity cars, where there are two brake systems, there will be an extra brake wheel on the "A" end. To add strength, manufacturers usually ad various patterns of ripples to box car and flat car ends.

bulletThe regular brake wheel and retainer valve are on the "B" end as well as another ladder to reach them. In modern cars, the retaining valve has been moved under the car as part of the control valve. The retainer valve was introduced in the late 1920s along with "A-B" brakes. It allows a brakeman to set the carís brakes to a predetermined degree of "on" so that in a heavy braking condition, such as downgrades, a locomotive does not have to use as much air to fully set all the train brakes. Under normal circumstances the brake wheel is used to manually set the brakes when a car is spotted.

That describes the major components of a model railroad car. Make sure the brake cylinder points toward the "B" end of the car. Railroads usually paint the brake wheel the same color as the car body.

Meeting Standards

For smooth operation, most clubs require that your car meet certain standards. Install Kadee couplers according to the instructions, taking care to burnish the shaft hole. Be careful to not damage the springs. Add any additional weight to the car according to the list of minimum weights shown below before you fasten the chassis to the body. Check the wheel gauge and reinstall them in the trucks. With the car assembled, check the coupler height for proper clearances.

If you follow all these steps, your cars will pass inspection every time. For a car to meet the standards for certification, it must be the correct weight, the wheels and couplers must be in gauge and move freely, the trucks must move freely in all directions but be stable, and the body must be secured to the frame. In addition, our club now requires metal wheels on all rolling stock.

Hint: On Athearn kits, you should remove the shaft from the truck bolster. This allows you to tighten the trucks enough to avoid wobbling.

NMRA Car Weighting Recommendations

According to NMRA recommended practice 20.1, the weight of an HO car is one initial ounce plus 1/2 ounce for each inch of car length.


Prototype (feet) HO (inches) Weight (ounces)
30 4 3
40 5 1/2 3 3/4
50 6 7/8 4 1/2
60 8 1/4 5 1/8
70 9 5/8 5 3/4
80 11 6 1/2
87 12 7

copyright 1998 by Santa Susana Railroad Historical Society.

Hosted By