This item is covered in the US Patent and Trademark office. It is US patent number 3,313,244 (granted 11 April 1964, filed May 15 1964)
While Alco and GE used span bolster in their dual high horsepower freight locomotive, EMD engineer Ludvil F. Koci designed this truck since the truck weights less than a dual B truck with its span bolster. In addition a span bolster raises the height of the locomotive which means a higher center of gravity.
The patent has two claims, both are very technical and not spelled out in layman terms. You can view this patent on the USPTO.gov web site once you download the TIFF reader on your computer or use another web site if the supprt patents before 1977.
While Alco and GE used span bolster in their dual high horsepower freight locomotive, EMD engineer Ludvil F. Koci designed this truck since the truck weights less than a dual B truck with its span bolster. In addition a span bolster raises the height of the locomotive which means a higher center of gravity.
The patent has two claims, both are very technical and not spelled out in layman terms. You can view this patent on the USPTO.gov web site once you download the TIFF reader on your computer or use another web site if the supprt patents before 1977.