The BOT then ordered ten new prototype subway cars made of stainless steel from the Budd Company. These R11 cars, so called because of their contract number, were delivered in 1949 and specifically intended for the Second Avenue Subway. They cost US$100,000 (equivalent to $ in ) each; the train became known as the "million dollar train". The cars featured porthole style round windows and a new public address system. Reflecting public health concerns of the day, especially regarding polio, the R11 cars were equipped with electrostatic air filters and ultraviolet lamps in their ventilation systems to kill germs.