the air brakes if the controller handle was released for any reason, causing the car to come to an abrupt stop. A longer, double-truck version of the Birney car was developed in the 1920s, incorporating its most successful features. These were sold to a number of systems, including that of Tampa, Florida, and to the Texas Interurban Railway, which used them exclusively. In addition to 11 double-truck passenger cars, which featured deluxe interior appointments and toilets for interurban service, the Texas Interurban operated three unusual Birney-based double-truck express cars without passenger seats or windows– the only cars of this type ever built. Decline Thousands of the cars were purchased from their inception to a few years after the end of the war. Production peaked in 1920, with 1,699 cars built in that year alone, but then declined rapidly and ended in 1930. Birney cars began to fall from favor in part because of the features that had originally made them attractive. Their light weight could be a problem in snow that a heavier car could easily plow through. Their short length made their ride quality comparatively poor, and on poorly maintained track they derailed easily. The public began to deride them as flimsy. Their limited passenger capacity rendered them unsuitable for busy routes and rush hour service, causing them to be relegated to minor lines or to be sold mostly to small-town streetcar systems. The streetcar companies also found that the safety features of the Birney, such as the use of interlocked doors to prevent the car from starting if a door was open or a passenger was stuck, could be incorporated in larger cars and that the public was not as disturbed by the absence of the conductor as the companies had feared. International use Its initial rise and fall notwithstanding, the Birney car was useful and durable, and many were shipped to streetcar systems in other countries, especially ones located in smaller cities and towns, where they served for additional decades. For example, the city of Halifax, Nova Scotia, Canada, bought up Birneys secondhand from other systems (including 22 acquired from the Toronto Transportation Commission (TTC) and five from Bakersfield and Kern Electric Railway) across North America to build an "all-Birney fleet" and keep its streetcar system going in the difficult years of the Great Depression and World War II, finally retiring its last car in 1949. The