Closely follow directions, as some pieces must be glued and others will be snapped into place. Use glue sparingly for a clean, realistic finish. Put the coupler on the peg found underneath and at the end of the car, and place the cover plate over the coupler. Don't glue this piece, as that would interfere with the movement of the coupler, and don't overtighten the screw. Once the screw is in place, check the coupler for free movement.
Trucks are what model railroaders call the wheels on the cars.
Check to make sure the wheels rotate freely. Place the completed truck on the bottom of the freight car, and screw it into place. Make sure the truck has free movement in all directions so the car can move smoothly around corners. Repeat the process at the other end of the railcar. DIY Model Railroads host Ted Brown and model railroaders Kent McBee and Pamela Lindsey offer tips on finishing the project.