On May 31 , 1889 , the South Fork Dam collapsed upstream of Johnstown on the Little Conemaugh River . The resulting deluge devastated the city , killing 2,209 people . As the city rebuilt , the Cambria Iron Company started work on a residential development atop Yoder Hill . To provide easy transportation on the steep slope for residents of the new community of Westmont , the company constructed an inclined plane . In addition to being a convenient mode of transportation , the Johnstown Inclined Plane doubled as an escape route in event of flood . Diescher was hired by Cambria Iron to design the incline . The rails used in the incline were manufactured in Johnstown at Cambria Iron , and many of the construction tools handcrafted there . The Inclined Plane Bridge was built to span the Stoneycreek River to provide access to the lower station of the incline . Originally named the Cambria Inclined Plane , the Johnstown Inclined Plane opened on June 1 , 1891 and cost $ 133,296 to build . The convenience the incline provided stimulated a rapid growth of population in Westmont and made the borough one of the country 's first suburbs . Over 40 million trips were taken on the incline in its first 80 years of operation
resulting deluge
Johnstown Flood
Johnstown Inclined Plane