Some flatcar loads while relativly small were so heavy they exceded the axle loading limit for a standard (2 bogie) flatcar.
Several Railroads modified flatcars by replacing the normal 2 bogies with two bolsters with bogies at each end which then attached to the
underside of the car body in the same manner as the original single bogie. This reduces the axle loading by almost half. This is the body section
of an empty car with an attachment point (a.load0) in the center. Down-loaders can make custom loads and attach them to this car, Assemble this
car in Surveyor by placing the body section on the track then select the bolster (kuid2:210518:6501:1) and place them half way between the center
of the body and each end. When properly assembled there will onl;y be 1 red and 1 green arrow and the car will move as a unit.