Some flatcar loads while relativly small were be 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
with a steamship crank shaft assembly as a load. 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 car and each end.