A Birney or Birney Safety Car is a type of streetcar that was manufactured in the United States in the 1910s and 1920s. The design was small and light and was intended to be an economical means of providing frequent service at a lower infrastructure and labor cost than conventional streetcars. Production of Birney cars lasted from 1915 until 1930, and more than 6,000 of the original, single-truck version were built. Several different manufacturers built Birney cars. The design was "the first mass-produced standard streetcar (albeit with minor variations)" in North America. Invention The Birney car was the joint 1915 invention of Charles Birney and Joseph Bosenbury (who was issued the patents in 1917 and 1919, and assigned half to Birney; see Brill page 140). Birney was an engineer with the firm of Stone & Webster, an operator of a number of trolley systems in the United States in the early part of the 20th century. The design was named the "Safety Car", and became known as the "Birney Safety Car" and ultimately simply as the "Birney" car. The vehicle was a return to single-truck (single-bogie) streetcars. Birneys were small and light, about a third the weight of conventional cars of the period; were of rugged, standardized construction; mass-produced and inexpensively built. Twin motors gave them nimble acceleration. Birney cars averaged about in length and typically had seating for about 32 passengers. The largest producer of Birney Safety Cars was the American Car Company, a subsidiary of the J. G. Brill Company, but several other companies also manufactured Birneys (e.g. Ottawa Car Company). Benefits and safety features The Birney was designed to operate with only a motorman, saving the cost of the conductor. The advent of World War I made single-person operation additionally attractive as it addressed the wartime labor shortage. When labor was available, Birneys could be operated at more frequent intervals, prompting the slogan "A Car in Sight at all Times". This latter attraction was one of the street railway industry's first attempts to deal directly with automobile competition. The Birney Car also introduced the use of pneumatically balanced and interlocked doors. If a door was stuck open, or a passenger or other object blocked the door, the motors could not be started. The controls on the Birney Car also included an early application of the "deadman control". This device removed power from the car's motors and applied