image/1531.jpg, 53.9K

Thrall center-beam flatcar - Thrall built 120 of the prototype cars in 1986 for Union Pacific.  Prior to this, lumber was hauled on traditional flatcars.  The flatcars were easy to load, but pagued by the shifting of the load.  Bulkheads were added to stabilize the load, but this also added more weight.  Next they attempted to make the cars lighter by reducing the center sill and adding a tall beam down the center to make up for the lost strength.  The partition also added strength to the bulkheads so that they could be made lighter.  Thrall made the first such car in 169 following a Candian Naional design.  The final move was to replace the center beam with a truss which would reduce the weight even further which also resulted in an additional 10 percent capacity.

previous / next
return to index