Established in 1850 with the town of Altoona, the Pennsylvania Railroad's Altoona Works grew into what was once the greatest railroad shop complex in the world, sprawling across 218 acres in 122 buildings with 88 acres under roof, 4,500 machine tools, and 94 overhead cranes. Four distinct groups of buildings emerged to meet the railroad's need to build, test, repair, and rebuild its vast fleet. From 1866 to 1946, 6,873 steam, diesel-electric, and electric locomotives were built here, along with thousands of freight and passenger cars, including some of the nation's first all-steel cars; 16,415 freight cars alone were built from 1921 to 1940. At its peak, the shops employed 16,500 workers, and around 1928 the entire complex was named Altoona Works. The original Altoona Machine Shops occupied this area, with three roundhouses for servicing locomotives and four buildings where the Test Department evaluated everything from drinking water and light bulbs to steam locomotives; just west stood the Locomotive Test Plant, where engines could be run up to 100 mph on a treadmill while analysts observed them. In 1938, after locomotive repair work was moved elsewhere in Altoona, this complex was renamed 12th Street Car Shops. The Juniata Shops, built in 1888-1890 about a mile farther northeast along the main line to provide more locomotive-building space, later gained the Erecting and Machine Shop in 1924, a facility still used for diesel locomotive overhauls, while the Altoona yards stretched along this area and farther northeast, and a 52-stall roundhouse opened at East Altoona in 1904 for routine servicing of main line locomotives. When the original machine shops became cramped, the Altoona Car Shops opened in 1869 about a mile east along the main line to build and repair freight and passenger cars, then later were reduced after much freight car work moved to the half-mile-long Samuel Rea Car Shop in nearby Hollidaysburg, which opened in 1955. As the Pennsylvania grew into the nation's single most important railroad, the South Altoona foundries complex opened in 1904 two miles southwest, taking over all foundry work from the Altoona machine shops and housing an oil mixing plant that formulated grease and lubricants for the entire railroad. At Christmas time in 1931, a devastating fire destroyed the air brake shop, machine shop, paint shop, and wheel shop, and with the Depression underway they were never rebuilt. A major operation at the Works was reconditioning locomotives, and the first step was to dip the engine in lye for cleaning.