Pennsylvania Railroad Company. Office of Assistant Chief Engineer, Signals.

The post of Engineer of Signals was created on June 11, 1883, with the appointment of H. F. Cox. This move reflected the growing significance of automatic and semi-automatic signals in promoting safe operations.

On August 1, 1887, George D. Fowle succeeded Cox as Engineer of Signals. He held the position for twenty years, during which time the first generation of electric signals was completed. Fowle was in turn succeeded by Alexander Holley Rudd, who served for thirty years, the name of the office being changed to signal engineer in 1913. Rudd was acknowledged as a signal expert throughout the industry. In 1915, the company developed its distinctive position-light signal in which rows of yellow lights could show a vertical line for clear, a horizontal line for stop, and a 45-degree angle for caution.

With the merger of the former Lines West and the adoption of the Regional system on March 1, 1920, Rudd became Chief Signal Engineer. New improvements in the 1920s included the development of centralized traffic control (CTC) in which a single operator could work the all the switches and signals on an extended line of road from a single console; cab signals, which eliminated some of the danger of ignoring wayside signals through inattention or because of poor visibility; and several systems of automatic train control (ATC), originally developed for transit systems, in which passing a restrictive signal automatically tripped the brakes. Although ATC only protected against rear-end collisions or head-on collisions on single track, the Interstate Commerce Commission (ICC) mandated that each Class I railroad equip at least one division during the 1920s. Rudd believed that ATC was an unnecessary expense for a multiple-tracked railroad like the PRR's main lines and was able to win the substitution of cab signals alone in many cases.

Rudd retired on April 1, 1937, and was succeeded by H. L. Stanton with the title of Assistant Chief Engineer, Signals. Stanton was replaced by W. G. Salmonson on January 16, 1945, and his title was changed to Assistant Chief Engineer, Communications and Signals under the reorganization of November 1, 1955. Salmonson was followed by J. I. Kirsch on June 1, 1957. The office was restyled System Engineer, Communication and Signals on April 1, 1958, and so remained until the Penn Central merger in 1968.

From the description of Annual signal reports, 1921-1943. (Hagley Museum & Library). WorldCat record id: 123466639