WILLIAM K. MACCURDY was an American engineer at SRI International
that developed the Hydra-Cushion freight car for
Southern Pacific in
1954. Cushioned rail cars based on his design are still the standard.
SRI International in 1952 with a background in
shipbuilding; he was previously a naval architect. Donald J. Russell
Southern Pacific with SRI in 1954, and asked them to design
a new rail coupling ; in particular,
Southern Pacific was concerned
with the draft gear , the part that connects the couplings to the
rolling stock. In MacCurdy's design, the coupler has an extended
connection to the center of the railway car, combined with interleaved
fingers at each end of the railway car helping to absorb some of the
effects of acceleration.
The theory was tested in December 1954 by modifying an existing car
with the technology (initially known as the "Hydra-friction") in
Sacramento and placing it into relatively difficult service; the car
greatly exceeded expectations. The second iteration, bearing the more
widely known name of Hydra-Cushion , was introduced in April 1956, and
Southern Pacific built and deployed an additional 350 of these cars in
summer 1957. The average damage to freight was reduced to 1/25th of
MacCurdy left SRI to be the chief research engineer in the
Transportation Equipment Division of Evans Products Company , which
was licensed some of the proprietary information about the
Southern Pacific in 1957.
In 1964, MacCurdy and Southern Pacific's William E. Thomford received
Franklin Institute 's 1964
George R. Henderson Medal for
achievements "in the field of railway impact control and associated
car design, with resulting benefits in reducing lading and rolling
stock damage". In 1967,
Railway Age noted that "The 10th
anniversary of the cushion-underframe ... has to be one of the most
significant anniversaries in the annals of the industry."
* ^ A B C D E F G H I J Nielson, Donald (2006). A Heritage of
Innovation: SRI's First Half Century.
Menlo Park, California
Menlo Park, California : SRI
International. pp. 6–1 – 6–3. ISBN 978-0-9745208-1-0 .
* ^ Inventor William K. MacCurdy. "Direct-Acting Hydraulic
United States Patent and Trademark Office
United States Patent and Trademark Office .
* ^ Impact tests of cushion underframes and hydrafriction and
standard draft gears. Stanford Research Institute . 1955.
* ^ A B "Era of car cushioning began 10 years ago".
Railway Age .
1967-02-27. pp. 34–35.
* ^ "Softer Rides for Rail Freight". SRI Journal. 2 (2). 1958. pp.
* ^ "Railroad Hydra-Cushion". Timeline of Innovations. SRI
International . Retrieved 2013-07-01.
* ^ Modern railroads. 20. 1965. p. 166.
* ^ "A Research Accomplishment Acknowledged".
SRI International .
* ^ "Train Museum News" (PDF). Millbrae Life & Times. Millbrae
Historical Society . June 2008. Retrieved 201